When John was arrested suddenly he doubts Jesus as Messiah. In Matthew
"Are you really the Messiah we've been waiting for, or should we keep looking for someone else?"
This doesn't make sense. How should I understand it?
John was the last of the line of Old Testament prophets.
Mat 11:11 Verily I say unto you, Among them that are born of women there hath not risen a greater than John the Baptist: notwithstanding he that is least in the kingdom of heaven is greater than he.
The faith of the Old Testament saints is different than what we receive.
Hebrews 11:39-40 And these all, having obtained a good report through faith, received not the promise: God having provided some better thing for us, that they without us should not be made perfect.
We have the permanent indwelling of the Holy Spirit. We have new life in Christ now. John did what he was called to do and by the power of the Holy Spirit. It was not done through his understanding but through his faithfulness. Like most of Israel he had expectations about the kingdom and was mystified that not only had the kingdom not come, but he was in prison awaiting execution. It should be expected that he would wonder if he missed something.
Another example of faith without much comprehension can be found with Peter;
John 6:66-68 From that time many of his disciples went back, and walked no more with him. Then said Jesus unto the twelve, Will ye also go away? Then Simon Peter answered him, Lord, to whom shall we go? thou hast the words of eternal life.
It is interesting to note that Jesus does not give John any verbal assurance of his messiahship but directs his attention the the works he had done. I do not see John's doubts as doubts of faith, but of doubts of understanding. Jesus was in effect saying, "It is not for you to understand, just be assured having seen the power of God working."
Instead of an unsettling picture of John's weak faith, I see the comfort the Lord provides those who are faithful.