The souls in purgatory desire one thing only: to be consumed in the love of God. This ardent charity gradually purifies their imperfections and draws them ever closer to God until they obtain Him fully.
What will purgatory be like? Perhaps the greatest description of what a soul will experience in purgatory has been given to us by St. Catherine of Genoa.
St. Catherine was given the special grace to experience in this life, over the span of a few years, the actual sufferings of purgatory in her soul. This enabled her to give the Church a detailed account of the condition of the Holy Souls in Purgatory based on her personal experience.
Her masterful work, Treatise on Purgatory, is excerpted below.
THE SOULS IN PURGATORY LOVE GOD ALONE
This holy soul, while still in the flesh, was placed in the purgatory of the burning love of God, in whose flames she was purified from every stain of sin, so that when she passed from this life she might be ready to enter the presence of God, her most sweet love.
By means of that flame of love she comprehended in her own soul the condition of the souls of the faithful in purgatory, where they are purified from the rust and stain of sins, from which they have not been cleansed in this world…
As far as I can see, the souls in purgatory can have no choice but to be there; this God has most justly ordained by his divine decree… They are so contented with the divine dispositions in their regard; and with doing all that is pleasing to God in that way which he chooses, that they cannot think of themselves, though they may strive to do so.
They see nothing but the operation of the divine goodness which is so manifestly bringing them to God that they can reflect neither on their own profit nor on their hurt. Could they do so, they would not be in pure charity…
… Being established in charity, they can never deviate therefrom by any defect, and have no will or desire, save the pure will of pure love, and can swerve from it in nothing. They can neither commit sin, nor merit by refraining from it.
THE SOULS IN PURGATORY EXPERIENCE BOTH PEACE AND SUFFERING
There is no peace to be compared with that of the souls in purgatory, save that of the saints in paradise and this peace is ever augmented by the inflowing of God into these souls, which increases in proportion as the impediments to it are removed.
The rust of sin is the impediment, and this the fire continually consumes, so that the soul in this state is continually opening itself to admit the divine communication…
In purgatory the flames incessantly consume [the rust of sin], and as it disappears, the soul reflects more and more perfectly the true sun who is God. Its contentment increases as this rust wears away, and the soul is laid bare to the divine ray, and thus one increases and the other decreases until the time is accomplished.
The pain never diminishes, although the time does, but as to the will, so united is it to God by pure charity, and so satisfied to be under his divine appointment, that these souls can never say their pains are pains. On the other hand, it is true that they suffer torments which no tongue can describe nor any intelligence comprehend…
SEPARATION FROM GOD IS THE GREATEST PAIN OF PURGATORY
The source of all suffering is either original or actual sin. God created the soul pure, simple, free from every stain… when [God] finds a soul that is returning to the purity and simplicity in which she was created, he … kindles in her a fire of charity so powerful and vehement, that it is insupportable to the soul to find and obstacle between her and [God]; and the clearer vision she has of these obstacles the greater is her pain.
Since the souls in purgatory are freed from the guilt of sin, there is no barrier between them and God save only the pains they suffer, which delay the satisfaction of their desire.
And when they see how serious is even the slightest hindrance, which the necessity of justice causes to check them, a vehement flame kindles within them, which is like that of hell…
THE SOULS IN PURGATORY EXPERIENCE BOTH CONTENTMENT AND YEARNING
The souls in purgatory are entirely conformed to the will of God; therefore, they correspond with his goodness, are contented with all that he ordains, and are entirely purified from the guilt of their sins.
They are pure from sins, because they have in this life abhorred them and confessed them with true contrition, and for this reason God remits their guilt, so that only the stains of sin remain, and these must be devoured by the fire. Thus freed from guilt and united to the will of God, they see him clearly according to that degree of light which he allows them, and comprehend how great a good is the fruition of God, for which all souls were created.
Moreover, these souls are in such close conformity to God, and are drawn so powerfully toward him by reason of the natural attraction between him and the soul, that no illustration or comparison could make this impetuosity understood…
… the souls in purgatory have an assured hope of seeing him and of being entirely satisfied; and therefore they endure all hunger and suffer all pain until that moment when they enter into eternal possession of… Jesus Christ, our Lord, our Savior, and our Love.
THE SOUL ENTERS PURGATORY WILLINGLY OUT OF LOVE FOR GOD
… the soul, leaving the body, and not finding in herself that purity in which she was created, and seeing also the hindrances which prevent her union with God, conscious also that purgatory only can remove them, casts herself quickly and willingly therein. And if she did not find the means ordained for her purification, she would instantly create for herself a hell worse than purgatory, seeing that by reason of this impediment she is hindered from approaching her end, which is God; and this is so great an ill that in comparison with it the soul esteems purgatory as nothing. True it is, as I have said, like hell; and yet, in comparison with the loss of God it is as nothing.
I see that as far as God is concerned, paradise has no gates, but he who will may enter. For God is all mercy, and his open arms are ever extended to receive us into his glory. But I see that the divine essence is so pure--purer than the imagination can conceive--that the soul, finding in itself the slightest imperfection, would rather cast itself into a thousand hells than appear, so stained, in the presence of the divine majesty. "
Knowing, then, that purgatory was intended for her cleaning, she throws herself therein, and finds there that great mercy, the removal of her stains.\
THE SOUL EXPERIENCES INTENSE PAIN IN PURGATORY
"The great importance of purgatory, neither mind can conceive nor tongue describe. I see only that its pains are as great as those of hell; and yet I see that a soul, stained with the slightest fault, receiving this mercy, counts its pains as naught in comparison with this hindrance to her love.
"And I know that the greatest misery of the souls in purgatory is to behold in themselves aught that displeases God, and to discover that, in spite of his goodness, they had consented to it.
And this is because, being in the state of grace, they see the reality and the importance of the impediments which hinder their approach to God.
PURGATORY IS A REFINING FIRE
"Consider gold: the oftener it is melted, the more pure does it become; continue to melt it and every imperfection is destroyed. This is the effect of fire on all materials. The soul, however, cannot be annihilated in God, but in herself she can, and the longer her purification lasts, the more perfectly does she die to herself, until at length she remains purified in God. "
When gold has been completely freed from dross, no fire, however great, has any further action on it, for nothing but its imperfections can be consumed. So it is with the divine fire in the soul. God retains her in these flames until every stain is burned away, and she is brought to the highest perfection of which she is capable, each soul in her own degree. And when this is accomplished, she rests wholly in God. Nothing of herself remains, and God is her entire being.
When he has thus led her to himself and purified her, she is no longer passable, for nothing remains to be consumed. If when thus refined she should again approach the fire she would feel no pain, for to her it has become the fire of divine love, which is life eternal and which nothing mars.
THE SOULS IN PURGATORY EXPERIENCE SATISFACTION IN GOD'S MERCY
"I see that the souls in purgatory behold a double operation. The first is that of the mercy of God; for while they suffer their torments willingly, they perceive that God has been very good to them, considering what they have deserved and how great are their offences in his eyes. For if his goodness did not temper justice with mercy (satisfying it with the precious blood of Jesus Christ), one sin alone would deserve a thousand hells.
They suffer their pains so willingly that they would not lighten them in the least, knowing how justly they have been deserved. They resist the will of God no more than if they had already entered upon eternal life."
The other operation is that satisfaction they experience in beholding how loving and merciful have been the divine decrees in all that regards them.
THE MORE THE SOUL DESIRES GOD, THE GREATER THE PAIN, AND THIS PURIFIES THE SOUL
They see all things, not in themselves nor by themselves, but as they are in God, on whom they are more intent than on their sufferings. For the least vision they can have of God overbalances all woes and all joys that can be conceived. Yet their joy in God does by no means abate their pain."
"Any delay, then, causes the soul intolerable pain. The pain and the delay prevent the full action both of what is hers by nature, and of that which has been revealed to her by grace; and, not able as yet to possess and still essentially capable of possessing, her pain is great in proportion to her desire of God. The more perfectly she knows him, the more ardent is her desire, and the more sinless is she. The impediments that bar her from him become all the more terrible to her, because she is so wholly bent on him, and when not one of these is left she knows him as he is. "
As a man who suffers death rather than offend God does not become insensible to the pains of death, but is so illuminated by God that his zeal for the divine honor is greater than his love for life, so the soul, knowing the will of God, esteems it more than all outward or inward torments, however terrible; and this for the reason that God, for whom and by whom the work is done, is infinitely more desirable than all else that can be known or understood. "
And inasmuch as God keeps the soul absorbed in himself and in his majesty, even though it be only in a slight degree, yet she can attach no importance to anything beside. She loses in him all that is her own, and can neither see nor speak, nor yet be conscious of any injury or pain she suffers, but as I have said before it is all understood in one moment as she passes from this life.
And finally, to conclude all, understand well, that in the almighty and merciful God, all that is in man is wholly transformed, and that purgatory purifies him."
SEE CATHERINE OF GENOA TREATISE ON PURGATORY FOR MORE
Learn more from the saints about Purgatory here