Isaac was the subject of the tenth and most difficult
test of Abraham’s faith: G-d commanded Abraham to sacrifice Isaac as a burnt offering. (Gen
22). This test is known in Jewish tradition as the Akeidah (the
Binding, a reference to the fact that Isaac was bound on the altar).
But this test is also an extraordinary demonstration of Isaac's own faith,
because according to Jewish tradition, Isaac knew that he was to be sacrificed,
yet he did not resist, and was united with his father in dedication.
At the last moment, G-d sent an angel to stop the sacrifice. It is interesting
to note that child sacrifice was a common practice in the region at the time.
Thus, to people of the time, the surprising thing about this story is not
the fact that G-d asked Abraham to sacrifice his child, but that G-d stopped
him!
Judaism uses this story
as evidence that G-d abhors human sacrifice. In fact, I have seen some
sources indicating that Abraham failed this test of faith because he did not refuse to
sacrifice his son! Judaism has always strongly opposed the practice
of human sacrifice, commonplace in many other cultures at that time
and place.
Isaac later married Rebecca (Rivka), who bore him fraternal twin sons: Jacob (Ya'akov) and Esau. (Gen 25).
Sources: Judaism 101