'Sons of Levi' in the Bible

And these are the names of the sons of Levi, according to their generations; Gershon, and Kohath, and Merari. And the years of the life of Levi were a hundred and thirty-seven years.

Then Moses stood in the gate of the camp, and said, Who is on the LORD'S side? let him come to me. And all the sons of Levi assembled themselves to him.