Charles Ellicott Commentary 1 Chronicles 6:63

"Unto the sons of Merari [were given] by lot, according to their families, out of the tribe of Reuben, and out of the tribe of Gad, and out of the tribe of Zebulun, twelve cities." — 1 Chronicles 6:63 (ASV)

This verse is word for word the same as Joshua 21:7, omitting the one term “by lot.”