Mark 9:12
A good reading of Isaiah 49 through 53 will help with understanding this passage. Jesus answers a question and asks another one. Elijah would indeed come before the Messiah. But, Jesus asks, how is it that it is also prophesied that the Messiah would suffer and be rejected? He is trying to get these men to think about Scripture for themselves rather than just relying on what the scribes said. The scribes were a good source, but they were failing to see the whole picture.
Heavenly Father, thank you for giving us Christ! Thank you for giving us the truth. Thank you for encouraging us to understand and grow. You are not afraid of people who think and ask questions. I love you! Praise your Name! In the name of the Lord Jesus Christ I pray and praise you, Amen.