Oecumenius

And He came and took, that is the little scroll, from the right hand of the One seated on the throne. Therefore, when all those in heaven and on earth, and under the earth, wondered to open the little scroll or to look into it as it had been seen before, only Christ, the Son of God, who for us and through us became and remains what He was, took the little scroll.

Commentary on Revelation ↗

Irenaeus

Likewise does the Lord also say: "All things are delivered to Me by My Father;" manifestly by Him who made all things; for He did not deliver to Him the things of another, but His own. But in all things [it is implied that] nothing has been kept back [from Him], and for this reason the same person is the Judge of the living and the dead; "having the key of David: He shall Open, and no man shall shut: He shall shut, and no man shall open." For no one was able, either in heaven or in earth, or under the earth, to open the book of the …

Against Heresies Book IV ↗

Bede

And he came and took the book out of the right hand of Him who sat on the throne. The book from the right hand of God, the dispensation itself of the Incarnation, is said to have been received by the Son of Man from the Father and from Himself, according to what He is as God, because both, along with the Holy Spirit, dwell on the throne. For Christ, who is the Lamb in humanity, is Himself the right hand of the Father in Deity.

Commentary on Revelation ↗

Alcuin of York

And he came and took the book out of the right hand of him that sat on the throne. The right hand of him that sits on the throne is the same as the Lamb as it were slain in the midst of the throne, because the Son of God through whom the world was created and the Son of man through whom man was redeemed are not two, but one Christ. Therefore the Lamb, that is the Son of man, took the book, that is the plan for the salvation of man, to which every page of the Scriptures bears witness, from himself, that is from his divinity.

Commentary On Revelation ↗