When Moses had finished speaking these words to all Israel,
1 And Moses went and spake these words. By the word went he signifies that, having received the commands from God, he came to the people to report them. Hence we gather that they were warned in good time to beware, if they had been sensibly disposed.
Loth to part (we say) bids oft farewell. Moses does so to the children of Israel: not because he was loth to go to God, but because he was loth to leave them, fearing that when he had left them they would leave God.
Commenting on Deuteronomy 31:1-8
And Moses went and spake these words unto all Israel. The following words, even to the whole body of the people summoned together on this occasion. It seems that after Moses had made the covenant with them he was directed to, he dismissed the people to their tents, and went to his own, and now returned, having ordered them to meet him again, very probably...