Charles Ellicott Commentary Deuteronomy 13:6

"If thy brother, the son of thy mother, or thy son, or thy daughter, or the wife of thy bosom, or thy friend, that is as thine own soul, entice thee secretly, saying, Let us go and serve other gods, which thou hast not known, thou, nor thy fathers;" — Deuteronomy 13:6 (ASV)

If your brother. —The substance of this law is that individual idolaters might be executed in Israel. It justifies Jehu and Jehoiada in destroying Baal out of Israel and Judah (2 Kings 10:19–27; 2 Kings 11:18). It also accounts for the covenant made in the time of Asa (2 Chronicles 15:13), that whoever would not serve the Lord God of Israel should be put to death whether man or woman.

The law may seem harsh, but its principle is reproduced in the Gospel: He that loveth father or mother more than me is not worthy of me (Matthew 10:37). If any man come to me, and hate not his father, and mother, and wife, and children, and brethren, and sisters, yea, and his own life also, he cannot be my disciple (Luke 14:26).

It is impossible to deny or escape the identity of the Lord Jesus with the Jenovah of the Old Testament. He does not always put the execution of His judgments into human hands, but He is the same forever.