The Israelites complained about the food. Their tastebuds longed for onions, garlic, leeks, and fish, according to one verse, but as a whole, they wanted some meat; they had had enough of the manna. A few started the complaining, and the murmuring spread throughout. God got angry, and those people were consumed by His fire! Moses prayed, and God stopped.
The complaints persisted. Moses couldn't handle all these people at once, so God told him to appoint seventy elders to help him with the people. Doesn't this remind you of the 70 disciples Jesus picked to help the apostles? They cleaned themselves up, and God put his spirit upon them. Two young men outside the seventy assembled also received God's spirit and prophesied with the elders! Some were jealous and complained about that, too! Here's what Moses said:
And Moses said unto him, Enviest thou for my sake? would God that all the LORD'S people were prophets, and that the LORD would put his spirit upon them! Numbers 11:29
We have God's Spirit within us! They were jealous of what we have and the gifts to go along with having His Spirit. We need to realize our privilege.
God gave them more than what they asked for. He wanted them to have so much flesh that they would regret complaining. While the flesh was still in their teeth, they were overcome by a plague. What a good lesson for us; we are all guilty of complaining occasionally, but let us be careful to take it to God first and not spread discontent.