The Apostle Paul
Romans 5:11BSB·traditional attribution

Not only that, but we also rejoice in God through our Lord Jesus Christ, through whom we have now received reconciliation.

John Calvin Reformed @genevareformer

11. And not this only, etc. He now ascends into the highest strain of glorying; for when we glory that God is ours, whatever blessings can be imagined or wished, ensue and flow from this fountain; for God is not only the chief of all good things, but also possesses in himself the sum and substance of all blessings; and he becomes ours through Christ.

Matthew Henry Presbyterian @wholebiblehenry

The apostle here describes the fountain and foundation of justification, laid in the death of the Lord Jesus. The streams are very sweet, but, if you run them up to the spring-head, you will find it to be Christ's dying for us; it is in the precious stream of Christ's blood that all these privileges come flowing to us: and therefore he enlarges upon this...

Commenting on Romans 5:6-21

John Gill Reformed Baptist @doctorgill

And not only so, but we also joy in God,.... Something seems here to be understood, and which is to be supplied thus; not only we are saved by his life, and from wrath through him; not only are we reconciled to God by his Son, and Spirit; not only Christ has died for us while sinners and ungodly; not only do we glory in...