וַיְהִ֤י כַחוֹל֙ זַרְעֶ֔ךָ וְצֶאֱצָאֵ֥י מֵעֶ֖יךָ כִּמְעֹתָ֑יו לֹֽא־יִכָּרֵ֧ת וְֽלֹא־יִשָּׁמֵ֛ד שְׁמ֖וֹ מִלְּפָנָֽי׃
네 자손이 모래 같았겠고 네 몸의 소생이 모래 알갱이 같아서 그 이름이 내 앞에서 끊어지지 아니하였겠고 없어지지 아니하였으리라 하셨느니라
Rashi
a depth Heb. מְעִי, an expression of lowness and depth, like the depth of the seas (כִּמְעוֹת).
Radak
'והנה דבר ה, now G’d’s word in response to his concern about who would inherit him, saying: לא יירשך זה, this loyal servant of yours will not inherit you, כי אם אשר יצא ממעיך, do not err in your understanding of the meaning of the words לך ולזרעך, “to you and to your descendants,” I only referred to your biological; offspring. The word מעיים refers to all the organs within the body, in this instance referring to the reproductive organ. The word is used in a similar sense in Isaiah 48,19 וצאצאי מעיך, “your offspring.”