'Baptism' in the Bible

There came John baptising in the wilderness, and preaching the baptism of repentance for remission of sins.

And Jesus said to them, Ye do not know what ye ask. Are ye able to drink the cup which I drink, or be baptised with the baptism that I am baptised with?

And they said to him, We are able. And Jesus said to them, The cup that I drink ye will drink and with the baptism that I am baptised with ye will be baptised,

The baptism of John, was it of heaven, or of men? answer me.