For ye shall not go out with haste, nor go by flight: for the LORD will go before you; and the God of Israel will be your rereward.
For ye shall not go out with haste - as when ye left Egypt (Exodus 12:33; Exodus 12:39; Deuteronomy 16:3: cf. note, Isaiah 28:16). Ye shall have time to cleanse yourselves and make deliberate preparation for departure.
For the Lord will go before you - Yahweh, as your Leader in front (Isaiah 40:3; Exodus 23:20; Micah 2:13).
And the God of Israel (will be) your rereward - literally, will gather you up; i:e., bring up the rear of your host.