What is the origin of the saying 'here's mud in your eye'?

It comes from the Gospel of John 9:6-7. This is the story of Jesus healing the man born blind...by putting mud, made from spittle and dust, in his eyes and telling him to go wash it off in the Pool of Siloam.

It became common in WW! trenches, as mud was everywhere, and in everything, including the drinks.