It was reckoned
καθὼς Ἀβραὰμ ἐπίστευσεν τῷ Θεῷ, καὶ ἐλογίσθη αὐτῷ εἰς δικαιοσύνην.
Paul said that Abraham (καθὼς Ἀβραὰμ) believed (ἐπίστευσεν) God (τῷ Θεῷ). It was reckoned to him as righteousness (καὶ ἐλογίσθη αὐτῷ εἰς δικαιοσύνην). Paul next turned to the example of Abraham. Perhaps the Judaizers or Jewish Christian had mentioned Abraham as the source of circumcision. Abraham was the ideal person from whom all righteous people were descendants. Paul cited Genesis, chapter 15:6, “Abraham believed Yahweh. Yahweh reckoned it to him as righteousness.” Yahweh appeared in a vision to Abram and said to him not to be afraid because Yahweh would be his shield. Yahweh said that Abram would have his own heir and that his descendants would be like the stars in the heaven. Abram believed, so that Yahweh reckoned him as righteous. Paul based all his arguments about Abraham on this passage in Genesis. Do you believe in God?