Берешит 17:10 Комментарий: Rashi, Radak, Siftei Chakhamim & Rav Hirsch

'ביני וביניכם וגו BETWEEN ME AND YOU — “you” is plural and refers to all those belonging to Abraham who were then alive.

זאת בריתי, just as I keep and observe my end as spelled out in verse 7, so you must keep and observe it. The Torah employs the plural mode when speaking of Avraham and his descendants, i.e. תשמרו, as it had done in verse 9 when spelling the word אחריך, "after you,: with the letter י indicating such a plural. This covenant was to be between G'd (sing.) and the Jewish people (ph.)

As if it were written להמול ... [I.e.,] although it is in the imperative form, it cannot be a command. For the next verse states [the command]: “You shall circumcise...”

ובין זרעך אחריך AND THY SEED AFTER THEE — those who are yet to be born.

המול is an infinitive equal to לְהִמּוֹל just as you may say עַשׂוֹת in place of לעשות (i.e. the infinitive may be with or without ל prefixed).