John Wesley on Joshua 13:29

Of Manasseh - Not that thou desired it, as Reuben and Gad did, Numb 32:1, but partly as a recompence to Machir the Manassite, for his valiant acts against Og; and partly for the better defence of the other two tribes, by so considerable an accession to them, which also was without any inconvenience to them, because the country was too large for the two tribes of Reuben and Gad.