QUESTION—What relationship is indicated by διὰ τοῦτο ‘therefore’?
1. It refers forward to the purpose clause ‘in order that it might be in accordance with grace’ which immediately follows; that is, the reason the promised inheritance is received by faith is so that it might be a matter of grace [BECNT, ICC2, NAC, NICNT, NTC]: For this reason it is from faith, namely that it might be in accordance with grace.
2. It refers backward and draws a conclusion from what has been stated [AB, Gdt, HNTC, Ho, ICC1, Mor, Mu, SSA, TH; GW, KJV, NCV, NIV, NLT]. It refers backward to 4:14, and insists that promise, faith, and grace belong together inseparably [HNTC]. It refers backward to 4:13; since law and promise are incompatible, it has to be by faith [AB]. It refers backward to the impossibility of salvation by law [Mor] or that the divine plan could be achieved by law [ICC1]. Law and the promised inheritance are contradictory, since law knows no grace, so the inheritance must therefore be of faith and by grace [Mu]. Because the law only brings wrath, the fulfillment of the promise had to be on the basis of faith and grace [Gdt, Ho]. It draws a conclusion from all that is stated in 4:13–15; that is, because God’s blessings to Abraham were given because he believed God and not because of obeying law, we can conclude that we will receive what God has promised because we trust in him [SSA].
QUESTION—What is it that is from faith and in accordance with grace, and which is the implied subject of this sentence?
1. The implied subject is the promise [AYB, BECNT, Gdt, Ho, Mu, NAC, NICNT, NTC, SSA, TH, WBC].
1.1 It is the promised inheritance [AYB, BECNT, Gdt, Ho, NAC, NICNT, SSA].
1.2 It is the promise of salvation [NTC].
2. The implied subject is God’s plan of salvation [HNTC, ICC1, ICC2], or justification [St].
David Abernathy, An Exegetical Summary of Romans 1-8, 2nd ed. (Dallas, TX: SIL International, 2008), 333.