David seems to have considered himself capable of defeating Goliath from the first time he heard of Goliath's insults to Yahweh. The fact that he referred to Yahweh as the "living God"(v. 26) shows David's belief that Yahweh was still the same Person who could defeat present enemies as He had done in the past. His was the simple faith of a child. He had apparently heard about God's promises to Moses and Joshua that if the Israelites would attack their enemies God would defeat them (Deut. 31:1-8; Josh. 1:1-9). Faith in God always rests on a word from God in Scripture. Most of the Israelites took Goliath's challenge as defying Israel (v. 25), but David interpreted it as defying the living God, the only true God (v. 26). Here David's heart for God begins to manifest itself (cf. 16:7).
"Eliab sought for the splinter in his brother's eye, and was not aware of the beam in his own. The very things with which he charged his brother--presumption and wickedness of heart--were most apparent in his scornful reproof."187
"Eliab's anger is the anger of a man who feels small because of the Israelite army's inability to deal with Goliath, and he particularly resents looking small in the eyes of his young brother [whom Samuel had anointed king-elect instead of himself]."188
David continued to inquire about the prize for slaying Goliath, probably to make sure he understood what he would risk his life to obtain.
