A.T. Robertson Commentary Galatians 3:6

"Even as Abraham believed God, and it was reckoned unto him for righteousness." — Galatians 3:6 (ASV)

It was reckoned unto him for righteousness (ελογισθη εις δικαιοσυνην). First aorist passive indicative of λογιζομα. See on 1 Corinthians 13:5 for this old word. He quotes Ge 15:6 and uses it at length in Ro 4:3ff. to prove that the faith of Abraham was reckoned "for" (εις, good Koine idiom though more common in LXX because of the Hebrew) righteousness before he was circumcised. James (James 2:23) quotes the same passage as proof of Abraham's obedience to God in offering up Isaac (beginning to offer him). Paul and James are discussing different episodes in the life of Abraham. Both are correct.