Genesis 11:11

And Shem lived after he begat Arphaxad five hundred years, and begat sons and daughters.

And Shem lived, after he begat Arphaxad, five hundred years,.... So that his whole age was six hundred years, and therefore must live to the times of Abraham, and even throughout the life of that patriarch, or near the end of it; and if he was the same with Melchizedek, as is the general opinion of the Jews, and is embraced by many Christians, they had an interview with each other:

and begat sons and daughters; of whom we have no account, because the Messiah did not spring from them; the design of this genealogy being to carry down his direct line from Shem to Abraham: it is to be observed, that in the account of the patriarchs, and their children after the flood, it is not added as before the flood, "and he died", their lives being long, that remark is made; but the lives of these being shorter, and gradually decreasing, it is omitted. An Arabic writer {x} says, that Shem died in the month Elul, on a Friday, at the close of the year of the world 2758. A Jewish writer {y} says, he died in the fifteenth year of Jacob, and that he saw twelve generations; according to Bishop Usher, he died A. M. 2158.

{x} Elmacinus, p. 13. apud Hottinger. Smegma, p. 258.
{y} R. Gedaliah, Shalshalet, fol. 1. 2.