Sorry to see that you missed the point.
Abraham is saved when he first believed (Rom.4:3) and then grows in faith, showing that faith until his last test in Heb.11:17 where he is tried and passed then shows his close relationship with God, being called God's friend.(James 2)
By faith Abel offered unto God a more excellent sacrifice than Cain, by which he obtained witness that he was righteous, God testifying of his gifts: and by it he being dead yet speaketh (Heb.11:4).
Faith gives witness what one believes, by working, but works do not add to the faith, they are a result of it.
Sorry, but Genesis 12 is discussed as an act of righteousness BEFORE the event of Genesis 15. The faith of Abraham in Genesis 12 is the same faith expressed in Genesis 15. Paul uses identical language in Hebrews to describe both incidents as instances of faith in the same manner. Thus, Hebrews 11:10 and Hebrews 11:14-16.
Is it surprising that so few Protestant commentaries address Genesis 12 and the subject of justification, although Paul uses the very same language to describe BOTH Genesis 12 and 15? You are placing artificial definitions upon what Scripture describes as similar events.
Regards