John Gill Commentary Leviticus 20:8

"And ye shall keep my statutes, and do them: I am Jehovah who sanctifieth you." — Leviticus 20:8 (ASV)

And you shall keep my statutes, and do them
Not only those respecting the above things, but all others, which would be a means of preserving them from sin, and of promoting holiness in their lives and conversations:

I [am] the Lord which sanctify you :
who had separated and distinguished them from all other people on earth, and who had given them holy laws, as the means of holiness; and who only could and did sanctify internally, by his Spirit and grace, such or them as were sanctified in heart, as well as outwardly.