'Only Son' in the Bible

God said, “Take now your son, your only son [of promise], whom you love, Isaac, and go to the region of Moriah, and offer him there as a burnt offering on one of the mountains of which I shall tell you.”

The Lord said, “Do not reach out [with the knife in] your hand against the boy, and do nothing to [harm] him; for now I know that you fear God [with reverence and profound respect], since you have not withheld from Me your son, your only son [of promise].”

and said, “By Myself (on the basis of Who I Am) I have sworn [an oath], declares the Lord, that since you have done this thing and have not withheld [from Me] your son, your only son [of promise],