You will find the Israelites complained often! When God took them toward Canaan, He could have taken them a shorter way; but, He knew if they saw the warlike Philistines who inhabited the coast--they would run back to Egypt! (Exodus 13:17,17).

There was no problem about food. God was going to take care of them. He wanted them to learn to depend on Him. They even could have bought goods along the way. "Thou shalt sell me meat for money, that I may eat; and give me water for money, that I may drink: ..." (Deuteronomy 2:28a).

The reason they did not eat their flocks and herds: There was not enough for all. (See Numbers 11:21,22). "600,000" footmen times the average family of four means there were approximately 2,400,000 Israelites wandering in the wilderness. If they had eaten all their animals, they would have had no milk, cheese, beasts of burden to carry or pull wagons, or breeding stock when they got to Canaan. Joshua 5:12 tells us the manna ceased when they ate of the old corn of the land upon arriving.

We Christians can be sure, since our God sustained 2,400,000 complaining Israelites in the wilderness for 40 years, He can take care of us! "Casting all your care upon him; for he careth for you." (I Peter 5:8)