That thou shouldest enter into covenant with the LORD thy God, and into his oath, which the LORD thy God maketh with thee this day: That thou shouldest enter - לעבר leaber, to pass through, that is, between the separated parts of the covenant sacrifice. See Genesis 15:18 (note).
And into his oath - Thus we find that in a covenant were these seven particulars:
1. The parties about to contract were considered as being hitherto separated.
2. They now agree to enter into a state of close and permanent amity.
3. They meet together in a solemn manner for this purpose.
4. A sacrifice is offered to God on the occasion, for the whole is a religious act.
5. The victim is separated exactly into two equal parts, the separation being in the direction of the spine; and those parts are laid opposite to each other, sufficient room being allowed for the contracting parties to pass between them.
6. The contracting parties meet in the victim, and the conditions of the covenant by which they are to be mutually bound are recited.
7. An oath is taken by these parties that they shall punctually and faithfully perform their respective conditions, and thus the covenant is made and ratified. See Jeremiah 34:18, Jeremiah 34:19, and the notes on Genesis 6:18 (note); Genesis 15:18 (note); Exodus 29:45 (note); Leviticus 26 (note).