#But what can I do today to these my daughters, or to their children whom they have borne?

Laban uses a question to emphasize that there is nothing he can do. AT: "But, there is nothing I can do to bring my daughters and grandchildren back with me." (See: [[:en:ta:vol1:translate:figs_rquestion]])

#let it be for a witness

Here the word "witness" does not refer to a person, but it is used figuratively and refers to the covenant that Jacob and Laban are making. The covenant is spoken of as if it were a person who is there when they agree to act peacefully to one another. (See: [[:en:ta:vol2:translate:figs_personification]])