I was shown mercy because I acted in ignorance and unbelief. 1 Timothy 1:13
Man is relentless when he judges, for he has no mercy; he judges without love or compassion. It is normal for us to fail, to make mistakes, to be weak and be tempted. All this is because of our nature, which Christ knew and endured. That is why, when the time comes to judge us, He does so with love, while He encourages us to change and strengthen the weak areas that make us fall.
But this should not be an excuse to keep on doing what is wrong and rely on the fact that He will always forgive us, for when we know his word, it sets us free.
Paul saw the mercy of God when He forgave him all his sins. Even though he knew the Word, he had no revelation of it and acted out of ignorance. He pursued and killed Christians while he believed he was doing the right thing; that is why he was forgiven.
Paul, in the hands of man, would have been sentenced to death, but the One who knows everything had mercy of Him. Let us be filled with his love so we can be merciful and give an opportunity to those who have failed out of ignorance, or those who have acknowledged that they have been weak and let themselves be seduced by sin.