Rashi on Exodus 6:29/רש"י על שמות ו׳:כ״ט

1וידבר ה׳ AND THE LORD SPAKE — This is the self-same command which was mentioned before, viz., (v. 11) “Go in, speak unto Pharaoh, king of Egypt”, but because it (Scripture) broke off the narrative in order to record their genealogy it now reverts to it and begins it anew.

2אני ה׳ I AM THE LORD — I am powerful enough to send you and to carry out the matter on which I have sent you.