Angels / Messengers
In Genesis 3 many translations talk about the angel with the flaming sword that protects the entrance to the Garden of Eden. However these are a specific angel, called Cherubim – Hebrew translation H3742 – kᵊrûḇ. Cherubim are powerful, winged angelic beings who are often depicted as guardians of YHVS’s holy space, including the Garden of Eden and the Ark of the Covenant and His Throne. They are often depicted with four faces (a man, a lion, an ox, and an eagle) and four wings.
But here in Genesis 16 we have different “angels”. An angel as we think in western english terms – are really actually called Messengers, Hebrew translation H4397 – mal’āḵ.
YHVH uses a messenger to talk to people. Sometimes people won’t even know this is a messenger or “angel”, or that YHVH is trying to communicate. They might act like it is a normal human being. These Malak, bringing direct messages from YHVH appears to Abraham, Jacob, Moses, Balaam, the Prophets, etc..
Interesting fact : The prophet Malachi’s name (Malak), means messenger.
Circumcisions
Genesis 17:10-14 YHWH initiates the circumcision with Abraham and all the men who are part of his house/family. There are two circumcisions however, the second one is of the heart. This is not a new concept that is only applicable to the New Testament. Jeremiah 9:24-26 and Ezekiel 44:9 talks about circumcision of the flesh and the heart.