Purgatory is a place of purification where sinners go if they are not good enough to enter Heaven, but not bad enough to enter Hell. In Purgatory, the soul pays the debt of its sins and is made pure and holy before it is allowed to enter Heaven. Therefore, the pains and sufferings of Purgatory are not eternal.

"But by the prayers of the Holy Church, and by the salvific sacrifice, and by the alms which are given for their spirits, there is no doubt that the dead are aided, that the Lord might deal more mercifully with them than their sins would deserve." (St. Augustine)

"Let us help and commemorate them. If Job’s sons were purified by their father’s sacrifice (Job 1:5), why would we doubt that our offerings for the dead bring them some consolation? Let us not hesitate to help those who have died and to offer our prayers for them." (St. John Chrysostom)

"If only you knew with what great longing these holy souls yearn for relief from their suffering. Ingratitude has never entered Heaven." (St. Margaret Mary)

"We must say many prayers for the souls of the faithful departed, for one must be so pure to enter heaven." (St. John Vianney)

"I was talking with some souls who, while on their way from Purgatory to Heaven, stopped here to thank me because I remembered them in my Mass this morning." (Padre Pio)

"More souls of the dead from Purgatory than of the living climb this mountain to attend my Masses and seek my prayers." (Padre Pio)

Prayer
Pray for them. Hear Holy Mass for them. Pray the Rosary for them.

"Eternal Father,
I offer Thee the Most Precious Blood of Thy Divine Son, Jesus,
in union with the Masses said throughout the world today,
for all the Holy Souls in Purgatory,
for sinners everywhere,
for sinners in the Universal Church,
those in my own home and within my family.
Amen."

Our Lord told St. Gertrude the Great, that the following prayer would release 1,000 souls from Purgatory each time it is said. The prayer was extended to include living sinners which would alleviate the indebtedness accrued to them during their lives.

Penance
Fast for the holy souls.

Give Alms
Have Masses said for the Holy Souls. Donate money to charities for the Holy Souls.

Daily Offerings
Offer up to God your daily sufferings and pains to relieve theirs.

The Heroic Act
Offering to God in favor of the Souls in Purgatory all the works of satisfaction we practice during life and all the suffrages offered for us after death.

The Way of the Cross
It was revealed to a chosen soul that when one offers up the stations of the cross for the holy souls in Purgatory he obtains the release of 10,000 souls!