Because the Lord was not able to bring this people into the
land which he sware unto them
That though he brought them out of Egypt, he was not able to bring them through the wilderness into Canaan; and that though he had wrought many signs and wonders for them, he could work no more, his power failed him, he had exhausted all his might, and could not perform the promise and oath he had made:
therefore he hath slain them in the wilderness;
because he could not fulfil his word, and so made short work of it, destroying them all together, which Moses suggests would greatly reflect dishonour on him; and in this he shows, that he was more concerned for the glory of God than for his own.