Genesis 17:9

And the Lord said to Abraham, And thou shalt observe my covenant, thou and thy sons after thee in their generations.

‘VE’ATAH’ (AND AS FOR THEE), THOU SHALT KEEP MY COVENANT. Rashi commented, “The vav of ve’atah connects the verse with the preceding matter [in Verse 4]: ‘As for Me behold My covenant is with thee, and as for thee, thou shalt be careful to keep it.’ And what constitutes this ‘keeping’ of it? This is My covenant, which you shall keep, between Me and you — this applies to those who were then alive; and thy seed after thee — this applies to those who are yet to be born.” The Rabbi is correct in his interpretation of the plain meaning of the verse.
Now they have said concerning the reason for the commandment of circumcision that He has thereby placed a reminder in the organ of lust, which is the source of much trouble and sin, in order that it should not be used excepting where it is commandatory and permissible.
By way of truth,, Note 63. the meaning of the verse, Behold, My covenant is with thee, is similar in meaning to the verses: Behold, I am with thee; And He said, Certainly, I will be with thee; The Eternal our G-d be with us. He is thus saying that the covenant will be with him, and therefore he will be fruitful and multiply. After that He commanded that Abraham keep this covenant, and the circumcision will be as a sign of the covenant. Thus it is that this “sign” is as “the sign” of the Sabbath,. (Exodus 31:17.) and therefore circumcision sets aside the Sabbath. Understand this.

ואתה את בריתי תשמר, "just as I keep My part of the covenant, I want you to keep your part of My covenant. Unless the covenant is respected mutually it will be invalid.

ויאמר אלוקים אל אברהם, once G'd had changed Avram's name Moses never again spelled in the former way. Our sages have gone so far as to describe anyone referring to Avraham as Avram as having violated a positive as well as a negative commandment. (Bereshit Rabbah 46,8) They base this on the wording "your name shall not be called Avram, but your name shall be Avraham." (verse 5) Many people question this, pointing out that in Nechemya 9,7 we read אתה הוא ה' האלוקים אשר בחרת באברם , "you are the Lord G'd Who has chosen Avram." The answer is that perhaps what Nechemya meant was that G'd had chosen Avraham to be Avraham at a time when he was still known as Avram. According to the plain meaning of the text, the wording of the Torah is only a warning not to call Avraham by this former name, it is not part of the 613 commandments

ואתה את בריתי תשמר, G'd makes plain that the overriding condition upon which this covenant is based is the meticulous observance by Avraham and his descendants of the terms of this covenant. Avraham is to pass on this condition to his offspring as well as to his household.