'Spring' in the Bible

A spring does not pour out fresh water and bitter water from the same opening, does it?

Can a fig tree produce olives, my brothers and sisters, or a vine produce figs? Neither can a salt water spring produce fresh water.

He also said to me, "It is done! I am the Alpha and the Omega, the beginning and the end. To the one who is thirsty I will give water free of charge from the spring of the water of life.