Albert Barnes Commentary Matthew 22:35

"And one of them, a lawyer, asked him a question, trying him:" — Matthew 22:35 (ASV)

A Lawyer. This does not mean one who practiced law, as we use the term, but one learned or skilled in the law of Moses. Mark calls him "one of the scribes." This means the same thing. The scribes were men of learning, particularly men skilled in the law of Moses. He had heard him reasoning with the Sadducees and perceived that he answered them well; and he was thought to be better qualified to hold a debate with him (Mark). This man was probably of a candid turn of mind; perhaps willing to know the truth, and not fully entering into their malicious intentions, but acting as their agent (Mark 12:34).

Tempting him. Trying him. Proposing a question to test his knowledge of the law.