A.T. Robertson Commentary Romans 5:21

"that, as sin reigned in death, even so might grace reign through righteousness unto eternal life through Jesus Christ our Lord." — Romans 5:21 (ASV)

That--even so grace might reign (ινα--ουτος κα η χαρις βασιλευση). Final ινα here, the purpose of God and the goal for us through Christ. Lightfoot notes the force of the aorist indicative (εβασιλευσεν, established its throne) and the aorist subjunctive (βασιλευση, might establish its throne), the ingressive aorist both times. "This full rhetorical close has almost the value of a doxology" (Denney).