In Genesis 32:7-12 and Genesis 32:13-32 note that Jacob alternately uses means as though there were no such thing as prayer; and then prays as though there were no such things as means. We may use means, but not trust in them.
and. The Figure of speech Polysyndeton (App-6) shows the care with which he prepared.
two bands. two camps. Same word (and perhaps idea) as in Genesis 32:2.