Walk contrary to you: see verse 21.

I myself: literally “indeed I.” An emphatic form of the pronoun, underlining the fact that God will act personally and not through an agent.

Smite you: this is not the same root verb as translated “be smitten” in verse 17. Here the meaning is more like “afflict” or “punish.” And it is God himself who is the subject of this verb.

Sevenfold: see verse 18.

Quoted with permission from Péter-Contesse, René and Ellington, John. A Handbook on Leviticus. (UBS Helps for Translators). New York: UBS, 1990. For this and other handbooks for translators see here .