The Apostle Paul
Romans 1:4ESV·traditional attribution

and was declared to be the Son of God in power according to the Spirit of holiness by his resurrection from the dead, Jesus Christ our Lord,

John Calvin Reformed @genevareformer

4. Declared “Declaratus,” ὁρισθέντος. Some of the ancients, such as Origen, Chrysostom, Cyril, and others, have given to this verb the meaning of is “proved — δειχθέντος;” demonstrated — ἀποφανθέντος;” “exhibited — ἀποδειχθώντος;”etc. But it is said that the word has not this meaning in the New Testament, and that it means, limited, determined, decreed, constituted.

Matthew Henry Presbyterian @wholebiblehenry

In this paragraph we have, I. The person who writes the epistle described (Rom 1:1): Paul, a servant of Jesus Christ; this is his title of honour, which he glories in, not as the Jewish teachers, Rabbi, Rabbi; but a servant, a more immediate attendant, a steward in the house. Called to be an apostle.

Commenting on Romans 1:1-7

John Gill Reformed Baptist @doctorgill

And declared to be the Son of God,.... Not made as he is said to be before, when his incarnation is spoken of; nor did he begin to be the Son of God, when he was made of the seed of David, but he, the Son of God, who existed as such, from everlasting, was manifested in the flesh, or human nature: and this his...