Repentance consists in no longer doing the same things. For he who reverts to the same sins is like a dog returning to his vomit, (2 Peter 2:22) and like the person who cards wool into the fire, or pours water into a container full of holes.
St. John Chrysostom
“For whatever our transgressions, and whatever we have done through the attacks of the adversary, let us pray that we may be forgiven…for it is good for a man to confess his failings rather than to harden his heart.”
St. Clement of Rome
“Enter into the Church to wash away your sins. From here there is a hospital and not a court of law. Do not be ashamed again to enter the Church; be ashamed when you sin, but not when you repent.”
St. John Chrysostom
The Lord calls to him all sinners; He opens His arms wide, even to the worst among them. Gladly He takes them in His arms, if only they will come to Him.” — St. Macarius of Optina
Note the Saint’s humility in the last sentence.
He that does not believe in the God Who saves is in difficult circumstances, but is faint-hearted; he that does not wish to render glory to God, that represents Him as not vigilant, but sleeping, not all-powerful and not merciful, thinks falsely of the God of Truth, and thus sins grievously. Especially inexcusable are faint-heartedness and unbelief in the man who has already been deemed worthy of often receiving marvelous help from God the Savior. Oh how great a sinner I am!
St. John of Kronstadt
Initially one thinks this is the typical “Hey all you sinners, stop it!” quote. While it is that, it is also St. John’s look in the mirror.
There is a sin which is always ‘unto death’ (1Jn 5:16): the sin for which we do not,
repent. For this sin even a saint’s prayers will not be heard.
St. Mark the Ascetic; On Those Who Believe They are Made Righteous by Works, v 44, The Philokalia
Someone was asked, ‘When will a man know that he has received the remission of his sins?’ He answered, ‘When in his soul he becomes conscious that he has completely hated them with his whole heart, and when he governs himself in his external actions in a manner opposed to his former way of life. Such a man, as having already hated his sin, is confident that he has received remission of his sins by the reason of the good witness of his conscience which he has acquired, after the saying of the Apostle, “A conscience is a witness of itself.”
St. Isaak the Syrian