Who against hope - Who against all apparent or usual ground of hope. He refers here to the prospect of a posterity; see Romans 4:19-21.
Believed in hope - Believed in what was promised to excite his hope. Hope here is put for the object of his hope - what was promised.
According to what was spoken - Genesis 15:5.
So shall thy seed be - That is, as the stars in heaven for multitude. Thy posterity shall be very numerous.