John [the Baptist] effectively said, “One greater than me is coming [v.7].
He is so great, I am not worthy to do what only a Gentile slave would do [v.7].
My baptism is outward with water: a symbol. His baptism is inward with the Spirit: the real thing [v.8].
The One who is coming is mightier than I am! He is more worthy than I am!
He is more powerful than I am! I have touched your body with water.
He will touch your soul with the Holy Spirit!
I know who I am in God’s plan. I know who He is in God’s plan too!”
— Danny Akin, Christ-Centered Expository Commentary: Mark, 8 (line breaks added).