Now the Lord had been supplying them with manna to sustain them through the desert, "manna from heaven", a unique food. "The rabble with them ..." A small group of people began to crave meat, and this led to the whole people complaining and wailing. It is relatively easy for a small group of moaners to infect the whole body. This is why we need to be careful about what and who we are influenced by.
The people started reminiscing about the wonderful food they had had back in Egypt. Now the people were in slavery in Egypt and were being harshly treated, so it is highly unlikely that they were eating choice food! Moreover, the reason the Lord rescued them was because He had heard their crying and seen their misery (Exodus 3:7), so they had been complaining in Egypt as well. We need to watch our emotions, and guard our thinking. An awful lot of what we think, feel and say is a load of nonsense!
The Lord was angry and Moses became troubled. Moses first reaction was to complain about his lot in life. Why was he lumbered with the task of looking after this mass of ungrateful and complaining people? Moses just wished he was dead, he had had enough.
The people complained, Moses complained. So was Moses no better than the people? No, the difference is that Moses complained to God. When we complain to God we may end up being rebuked, we will always end up discovering that God is right, but we will also be changed.
God gives Moses extra people to help him, and says he will give them some of the power of the Spirit. Moses was empowered by the Holy Spirit, and this empowering would spread to more people. We have here a hint of what would happen at Pentecost and beyond.
So Moses receives something from God that will help him. The people would also receive something from God, but this would make them sick of it. In fact they would receive what they were craving. Notice that in complaining against Moses the people were rejecting God.
Moses cannot see how God can supply all this meat. So like Abraham before him, Moses doubts God's ability to do what He has promised.
Two extra men received the Spirit as well. The Holy Spirit does not always follow nice neat rules. Joshua thinks this is something that must be stopped, but Moses knew that life would be a lot easier if only everyone was filled with the Spirit.
The quail came, but also a plague, which seems to have focused on those who started the complaining.