Even if we have thousands of acts of great virtue to our credit, our confidence in being heard must be based on God's mercy and His love for men. Even if we stand at the very summit of virtue, it is by mercy that we shall be saved.
If you have received from God the gift of knowledge, however limited, beware of neglecting charity and temperance. They are virtues which radically purify the soul from passions and so open the way of knowledge continually.
Great is this mystery, and great is the mercy of God towards man. If all the people of the earth knew how deeply the Lord loves man their hearts would be filled with love of Christ and Christ’s humility, and they would seek to be like Him in all things. But man cannot do this by himself, for it is only in the Holy Spirit that he can become like unto Christ. Man that is fallen purifies himself through repentance, and is made new by the grace of the Holy Spirit, and in all things becomes like unto the Lord.
If someone is judged worthy to receive the gift of knowledge but allows his heart to be full of bitterness or rancor or aversion to another, it is as if he had been struck in the eye by a thornbush. That is why knowledge is no good without charity.
It is more serious to lose hope than to sin. The traitor Judas was a defeatist, inexperienced in spiritual warfare; as a result he was reduced to despair by the enemy's onslaught, and he went and hanged himself. Peter, on the other hand, was a firm rock: although brought down by a terrible fall, yet because of his experience in spiritual warfare he was not broken by despair, but leaping up he shed bitter tears from a contrite and humiliated heart. And as soon as our enemy saw them, he recoiled as if his eyes had been burnt by searing flames, and he took flight...
If you examine your life well, you will find many instances when God showed His unmistakable mercy to you. Trouble was brewing, but it passed you by for some reason. God delivered you. Acknowledge these and thank God, Who loves you.