It would have been very unusual to be circumcised in a time of war. When men are circumcised they are unable to move without pain or to defend themselves in battle for several days. (See: [[rc://en/tw/dict/bible/kt/circumcise]])
Yahweh stops providing manna in this chapter and will no longer provide them with their daily allotment of food. This does not mean Yahweh's care and provision will stop.