That being justified by his grace, we should be made heirs according to the hope of eternal life. That, being justified by his grace - Being freed from sin; for the term justification is to be taken here as implying the whole work of the grace of Christ on the heart, in order to its preparation for eternal glory.
Should be made heirs - The Gospel not only gave them the hope of an endless state of glory for their souls, but also of the resurrection and final glorification of their bodies; and they who were children of God were to be made heirs of his glory. See the note on Galatians 4:6, Galatians 4:7.