Albert Barnes Commentary Leviticus 19:2

"Speak unto all the congregation of the children of Israel, and say unto them, Ye shall be holy; for I Jehovah your God am holy." — Leviticus 19:2 (ASV)

Ye shall be holy... - These words express the keynote to the whole book of Leviticus, being addressed to the whole nation. There does not appear to be any systematic arrangement in the laws which follow. They were intended as guards to the sanctity of the elect people, enforcing common duties by immediate appeal to the highest authority. Compare the note on Leviticus 18:24-30.