2 Maccabees 12:46: "Thus he made atonement for the dead that they might be freed from sin.
Matthew 5:26 "Amen, I say to you, you will not be released until you have paid the last penny."
Matthew 12:32 says, "And whoever speaks a word against the Son of Man will be forgiven; but whoever speaks against the holy Spirit will not be forgiven, either in this age or in the age to come."
Many popular devotional practices involve veneration of the saints. The saints have a special place in the Body of Christ, which includes both the living and the dead. Through Christ we on earth remain in communion both with the saints in heaven and with the dead who are still in Purgatory. We can pray for those in Purgatory and ask the saints to pray for us. Through their prayers of intercession, the saints in heaven play an integral role in the life of the Church on earth. "For after they have been received into their heavenly home and are present to the Lord, through Him and with Him and in Him they do not cease to intercede with the Father for us, showing forth the merits which they won on earth through the one Mediator between God and man." The saints, the members of the Church who have arrived at perfect union with Christ, join their wills to the will of God in praying for those in the Church who are still on their pilgrimage of faith.
Besides what the saints can do for us by their prayers, the very practice of venerating the saints does great good for those who are devoted to the saints. By practicing love of the saints we strengthen the unity of the entire Body of Christ in the Spirit. This in turn brings us all closer to Christ. "For just as Christian communion among wayfarers brings us closer to Christ, so our companionship with the saints joins us to Christ, from Whom as from its Fountain and Head issues every grace and the very life of the people of God." Love of the saints necessarily includes and leads to love of Christ and to love of the Holy Trinity. "For every genuine testimony of love shown by us to those in heaven, by its very nature tends toward and terminates in Christ who is the 'crown of all saints,' and through Him, in God Who is wonderful in his saints and is magnified in them."
—From Popular Devotional Practices