Genesis 25:6

But unto the sons of the concubines, which Abraham had, Abraham gave gifts, and sent them away from Isaac his son, while he yet lived, eastward, unto the east country.

Geneva Bible - But unto the (b) sons of the (c) concubines, which Abraham had, Abraham (d) gave gifts, and sent them away from Isaac his son (while he yet lived) Eastward to the East country.
(b) For by the virtue of God's word he had not only Isaac, but begat many more.
(c) Read Genesis 22:24 .
(d) To avoid the dissention that else might have come because of the heritage.

Genesis 22:24

And his concubine, whose name [was] Reumah, she bare also Tebah, and Gaham, and Thahash, and Maachah.


Geneva Bible - And his (i) concubine called Reumah, she bare also Tebah, and Gaham, and Thahash and Maachah.
(i) Concubine is often times taken in the good part for those women which were inferior to the wives.