'Baptism' in the Bible

In the wilderness John the baptizer began preaching a baptism of repentance for the forgiveness of sins.

But Jesus said to them, "You don't know what you are asking! Are you able to drink the cup I drink or be baptized with the baptism I experience?"

They said to him, "We are able." Then Jesus said to them, "You will drink the cup I drink, and you will be baptized with the baptism I experience,

John's baptism -- was it from heaven or from people? Answer me."