Rather than get worked up and succumb to the temptation to despair, you must desire and earnestly strive to be truly sorry for all your offenses against God, even the ones that are hidden from you, resolve yourself to accept wisdom and grace from God so that you may know what the offenses may be and to amend your life, no matter how difficult it should prove, no matter how great the sacrifice, knowing this: if you put your interests and desires before the interest of truth, you will be kept blind by your own bad will. With the latter disposition, we can be confident of only death and hell, but with the former disposition, we can be confident that God will be pleased to give us the truth that we so earnestly desire. God's grace is not wanting. All you need is to ACCEPT IT.
St. John Chrysostom, Homily on 2 Corinthians: Then beginning the prayer, he says, "That the all-pitying and merciful God would listen to their prayers." For that you may not say, What shall we pray? They are aliens, not yet united [to the body]. Whereby can I constrain the regard of God? Whence can I prevail with Him to impart unto them mercy and forgiveness? That you may not be perplexed with such questions as these, see how he disentangles your perplexity, saying, "that the all-pitying and merciful God." Heardest thou? "All-pitying God." Be perplexed no more. For the All-pitying pities all, both sinners and friends. Say not then, "How shall I approach Him for them?" Himself will listen to their prayers. And the Catechumens' prayer, what can it be but that they may not remain Catechumens? Next, he suggests also the manner of the prayer. And what is this? "That He would open the ears of their hearts;" for they are as yet shut and stopped up. "Ears," he says, not these which be outward, but those of the understanding, "so as to hear 'the things which eye has not seen, nor ear heard, neither have entered into the heart of man."" 1 Corinthians 2:9; Isaias 54:4
Louis de Montfort, The Secret of the Rosary: "If you say the Rosary faithfully until death, I do assure you that, in spite of the gravity of your sins "you shall receive a never fading crown of glory." Even if you are on the brink of damnation, even if you have one foot in Hell, even if you have sold your soul to the devil as sorcerers do who practise black magic, and even if you are a heretic as obstinate as a devil, sooner or later you will be converted and will amend your life and save your soul, if----and mark well what I say----if you say the Holy Rosary devoutly every day until death (all 15 decades) for the purpose of knowing the truth and obtaining contrition and pardon for your sins."
What Must You Do To Get to Heaven?