Moses had stood “in the gap” for his brothers. The concept of a gap between God’s intercessor and those in need of their prayers is introduced later in Israel’s history, in the days of the prophets who were responsible to tend the flock.
After Moses went down to the people and saw they were punished, he said to them,
“You have committed a great sin. But now I will go up to the Lord; perhaps I can make atonement for your sin.”
Then Moses went back to the Lord and said,
“Oh what a great sin these people have committed. They have made themselves gods of gold. But now, please forgive their sin–but if not, then blot me out of the book you have written.” (ibid., vs 32)
The Lord replied to Moses,
“Whoever has sinned against me I will blot out of my book. Now go, lead the people to the place I spoke of, and my angel will go before you. However, when the time comes for me to punish, I will punish them for their sin.” (ibid., vss 33, 34)
In this we see that there are limits to what intercession can accomplish, and that the Lord reserves the right to discipline his sons and daughters who stray and sin. We may stand in the gap and ask for mercy on behalf of our rebellious brothers and sisters, assisting them somehow in their deliverance from evil, but we cannot stand in their place, either to take their punishment or to save them from it. This passage reminds us that Christ came both to bear our punishment and to save us from God’s judgment.
Yes, there are limits to what intercessory prayers may accomplish. The intercessor may stand in the gap, but Christ alone is Savior.