Abraham set seven female lambs of the flock by themselves
"Abraham separated seven female lambs from the flock"
"7" (See: rc://en/ta/man/translate/translate-numbers)
What is the meaning of these seven female lambs that you have set by themselves?
"Why have you separated these seven lambs from the flock?"
you will receive
"you will take"
from my hand
Here "hand" stands for Abraham. AT: "from me" (See: rc://en/ta/man/translate/figs-synecdoche)
it may be a witness
The word "it" refers to the gift of seven lambs.
so that it may be a witness for me
The abstract noun "witness" can be stated as "to prove." AT: "to prove to everyone" (See: rc://en/ta/man/translate/figs-abstractnouns)