'Cup of' in the Bible

and whoever gives you a cup of water because you are Christ's, truly he shall not lose his reward.

And Jesus said to them, You know not what you ask. Can you drink of the cup of which I drink? or be baptized with the baptism with which I am baptized?

And they said to him, We can. And Jesus said to them, You shall drink of the cup of which I drink, and be baptized with the baptism with which I am baptized;