Genesis 25:1
1Abraham took another wife, and her name was Keturah.
Keturah is named as wife. Abraham’s household is larger than Isaac; later verse 6 will group her sons with the sons of Abraham’s concubines.
Arminian readers honor this marriage and children. God’s particular covenant with Isaac does not make other sons fictional or unloved.
After Sarah, Abraham takes Keturah. The genealogy is history, not a detour from the promise.
Reformed readers already know Isaac is the sworn seed (Gen 17; 21). Other sons will be listed as gift, not as rivals to the oath.