God’s unfailing love and his generous desire to forgive are not weakness or indecisiveness, nor are they reason to sin. Sin will have its effects, because God created a world of cause and effect. The murderer may repent, be forgiven, and lead a new life, but the effects of previous choices will continue to play out. We should not sin just because we know that God will forgive (see study note on 20:5–6).
a thousand generations: See Deuteronomy 7:9–11.
He will visit the iniquity of the fathers: Our sins affect future generations, but God limits the effects to three or four generations. See also Exodus 20:5–6.