Moses had many frustrations with the Israelites. He had complained to God on multiple occasions about them. But when God told Moses that He was going to wipe them out, Moses pleaded with God to relent.
God never was going to wipe these people out; He was testing Moses to see whether he would learn what it meant to be an intercessor. Would Moses stand in the gap and pray for the people, or would he throw them under the bus?
In John's gospel we find someone who faced a similar test. A desperate father whose son was at death's door heard about Jesus, humbled himself, and bowed before the Lord, asking Him to touch his dear son. Jesus answered, "Unless you people see signs and wonders, you will by no means believe" (John 4:48 NKJV
What kind of thing is that to say to someone with a dying child? But just as God did with Moses, Jesus was testing this man. Really, He wasn't directing the words to the child's father at all. He was saying them to the fickle crowds who wanted to be impressed.
The man just stood there, patiently waiting for Jesus to finish His sermon. Then he came right back to Jesus and said, "Sir, come down before my child dies!" He was an intercessor praying for his son.
Jesus told him, "Go your way; your son lives."
He stood in the gap. He pressed on.
God is still looking for intercessors today. Sometimes we will pray for something, and we won't get an answer right away. So we think that God is obviously saying no. But maybe God wants you to step up your game. Maybe He wants you to pray a little bit more. Maybe He wants you to not give up so easily.