Verse 9 literally rendered is “so that (or therefore) those of faith are blessed with the faithful (or believing) Abraham.” Two ideas are expressed: (1) Abraham believed and was blessed; (2) all who believe are blessed as he was. The source of the blessing in each case is God himself. Here again, belief is not simply mental assent, but trust and confidence in God.
Abraham believed and was blessed must be expanded in some languages to read “Abraham trusted God, and God blessed him.” What Abraham did, however, may be best considered as cause in some languages and therefore “Because Abraham trusted God, God blessed him.” Similarly, the resulting clause so all who believe are blessed as he was may be rendered as “therefore God blesses all those who believe in him, just as he blessed Abraham.”
Quoted with permission from Arichea, Daniel C. and Nida, Eugene A. A Handbook on Paul’s Letter to the Galatians. (UBS Handbook Series). New York: UBS, 1976. For this and other handbooks for translators see here .
