Luke 10:29

But he, desiring to justify himself, said to Jesus, "And who is my neighbor?" (Luke 10:29)

Three points:

1. He

The "he" here is a lawyer, not the type of lawyer we know today but a religious lawyer--an expert in God's law. He knew (?) the Law of God better than anyone. He maybe didn't obey the law, but he knew it.

2. Desiring

He was under conviction. He knew that what the Lord Jesus had said was the correct understanding of God's Law, but he was not willing to obey. The word desiring--willing in the King James--shows a want to justify his actions, his false beliefs, in short, his sin. This still happens all the time whether a person is religious or not.

3. Justify himself

Justify has the idea of showing that one is innocent. This lawyer asks a question, thinking that he can circumvent God's law. Perhaps he had done the very thing that Jesus had condemned. Whoever conceals his transgressions will not prosper, but he who confesses and forsakes them will obtain mercy. (Proverbs 28:13)
Let us face the truth about ourselves, confess our sins to God, ask forgiveness, and ask for His help to not do them any more.