You have a switch loop. You need to determine which cable is the power feed from the breaker and which is the switch cable.
Connect the power feed black to the switch cable white.
Connect the power feed white to the fixture white.
Connect thw switch black to the fixture black.
Connect all the grounds together.

Thanks for replying so quickly...Now another question.
He doesn't have a tester. Can he determine which line is the power feed to the breaker by testing it with the new light fixture?

This shows why it is important to take careful note of how things were wired when you disassemble them.

Connect any lamp to the black and white of ONE of the cables. Turn on the breaker and see if the lamp lights. Then connect it to only the other black and white at try again. This will tell you which one is powered. The other one is the switch loop. You could even take a floor lamp, turn it on, and hang its plug on the ceiling wires, making sure they didn't touch each other, for this test since that may be easier than holding a fixture up.

Then follow the directions by joed.

Thanks Joed and BillHart...it WORKED. Your advice and directions were right on..

he is lucky he did not have the switch ON! that would have been a direct short is he did. tell him next time to mark teh wires BEFORE he disconnects them.