he said - namely, to Moses (Deu 9:13). With God, saying is as certain as doing; but His purpose, while full of wrath against sin, takes into account the mediation of Him of whom Moses was the type (Exo 32:11-14; Deu 9:18, Deu 9:19).
Moses his chosen - that is, to be His servant (compare Psa 105:26).
in the breach - as a warrior covers with his body the broken part of a wall or fortress besieged, a perilous place (Eze 13:5; Eze 22:30).