Sforno on Deuteronomy 31:6/ספורנו על דברים ל״א:ו׳

1לא ירפך, for at the hour of battle G’d will lend you additional mental fortitude

2ולא יעזבך, neither will He abandon you afterwards by decreasing the attention He pays to your affairs. As a result, none of the neighbouring nations will dare attack you.