And he said, Lord God (Adonai Jehovah; vide Genesis 15:2), whereby shall I know that I shall inherit it? Not the language of doubt, though slight misgivings are not incompatible with faith (cf. 6:17; 2 Kings 20:8; Luke 1:34), and questioning with God "is rather a proof of faith than a sign of incredulity" (Calvin); but of desire for a sign in confirmation of the grant (Luther), either for the strengthening of his own faith, or for the sake of his posterity (Jarchi, Michaelis), or for some intimation as to the time and mode of taking possession (Murphy).
Rosenmüller conceives the question put in Abram's mouth to be only a device of the narrator's to lead up to the subject following.