For the children of Joseph were two tribes, Manasseh and Ephraim: therefore they gave no portion unto the Levites in the land, except cities to dwell in, with their pasture lands for their cattle and for their possessions.
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George Leo Haydock
Suburbs. A certain quantity of ground, which the Levites were not allowed to till or plant with vines. (Grotius) (Numbers xxxv. 4.)
The tribe of Manasses, which was divided, fell heir to the portion which would have been allotted to Levi, who was also scattered among his brethren. (Haydock)
Thus Joseph obtained the birth-right of Ruben. (Calmet)
Twelve portions were made, as Jacob had adopted Ephraim and Manasses, Genesis xlviii. (Worthington)