This law is for all the eternal generations and there is no circumcising of days and there is no passing a single day beyond eight days because it is an eternal ordinance ordained and written in the heavenly tablets. And anyone who is born whose own flesh is not circumcised on the eighth day is not from the sons of the covenant which the LORD made for Abraham since (he is) from the children of destruction. And there is therefore no sign upon him so that he might belong to the LORD because (he is destined) to be destroyed and annihilated from the earth and to be uprooted from the earth because he has broken the covenant of the LORD our God. Because the nature of all the angels of the presence and all the angels of sanctification was thus from the day of their creation. And in the presence of the angels of the presence and the angels of sanctification he sanctified Israel so that they might be with him and with his holy angels. (Jub. 15:25-27; trans. Wintermute)
Most of this is just saying you MUST circumcise sons on the eighth day, no more days nor fewer days. If someone is not circumcised precisely on the eighth day, they do not belong to the covenant and will ultimately be destroyed, annihilated, etc. But the reasoning at the end is what caught my attention: because this is the nature of the angels of the presence and sanctification since their creation. They are created with the sign of the covenant within them, and the sign of the covenant is circumcision. So, according to Jubilees, angels (or these highest orders of angels) are created already circumcised. These are also the same orders of angels that observed the Sabbath from the beginning of creation (Jub. 2:17-33). So, the angels that observe the sabbath alongside the Israelites are also circumcised like their human counterparts. The sabbath, recall, is also a sign of the covenant in the priestly tradition. So far, the only other thing these angels and covenanted humans share is Shavuot (Jub. 6:17-22) or the Feast of Weeks or the Feast of Oaths (which, by the way, begins tonight at sundown). Jubilees associates Shavuot with Noah: so we have Sabbath, Shavuot, and circumcision all shared by the elect angels and elect humans.