As Catholics, we have an assurance of mercy and salvation if we are faithful and keep God’s commandments (1 John 2:3). If we die in that state of purity and grace, we are assured of heaven. To make this to heaven, one must be perfectly holy and in a state of grace, because nothing that is unclean shall enter the Kingdom of God (Rev 21:27 – see also Is 4:4; Mal 3:2-4).
The purification and cleansing of any act of sin make us fit and worthy to be in the presence of God. This was clearly stated in St Paul’s writings and letters;
If any man’s work is burned up, he will suffer loss, though he himself will be saved, but only as through fire” (1 Cor 3:13, 15).
“For we must all appear before the judgment seat of Christ, so that each one may receive good or evil, according to what he has done in the body” (2 Cor 5:10).