Adam Clarke on Mark 1:4

John - The original name is nearly lost in the Greek Ιωαννης, and in the Latin Johannes, and almost totally so in the English John. The original name is יהוחנן Yehochanan, compounded of יהוה חנן Yehovah chanan, the grace or mercy of Jehovah: a most proper and significant name for the forerunner of the God of All Grace. It was John's business to proclaim the Gospel of the grace of God, and to point out that Lamb or sacrifice of God which takes away the sin of the world.

For the remission of sins - Or, toward the remission - εις αφεσιν. They were to repent, and be baptized in reference to the remission of sins. Repentance prepared the soul for it, and Baptism was the type or pledge of it. See on Mat 3:2 (note).