'In Their Generations' in the Bible

These are the names of the children of Levi in their generations: Gershon, Kohath and Merari. And Levi lived a hundred and thirty seven years.

The children of Merari are these: Mahli and Mushi: these are the kindreds of Levi in their generations.

It is a night to be much observed unto the LORD for bringing them out from the land of Egypt: this is that night of the LORD to be observed of all the children of Israel in their generations.