The word "Now" does not mean "at this moment," but is used to draw attention to the important point that follows. Alternate translation: "Therefore" (See: [[rc://en/ta/man/translate/figs-explicit]])
This is an idiom meaning to make a solemn oath witnessed by a higher authority, in this instance, God. Alternate translation: "promise me with God as your witness" (See: [[rc://en/ta/man/translate/figs-idiom]])
The two men had made a covenant with each other. The abstract noun "faithfulness" can be stated as "faithful" or "loyal." Alternate translation: "Be as faithful to me and to the land as I have been to you" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])