The mercy of God is what the thief on the cross enjoyed. He was condemned and nailed to the cross. But Jesus Christ had mercy on him. He received justification and ended up in paradise because he believed in Jesus. He never had the opportunity of hearing the doctrines but he believed that Jesus Christ was the son of God and he received the mercy of God.
We need God mercy in our lives. We should crave for this. The mercy of God will help us when we cannot help ourselves. The mercy of God will open closed doors for us. The mercy of God will save us from every condemnation. The mercy of God will blot out all our sins. We wish for the mercy of God.
Keeping the commandments of God will bring the mercy of God to us. We will receive the blessings of God in our lives if we obey His commandments. Practicing what God commands us in His Word will guarantee our receiving God's mercy.
The thief on the cross was saved when he didn't necessarily obey all the commandments when he was alive. He was not baptized nor did he obey Jesus while he was on earth. He only received mercy because he believed Jesus Christ when he saw Him on the cross.