A.T. Robertson Commentary Revelation 5:3

"And no one in the heaven, or on the earth, or under the earth, was able to open the book, or to look thereon." — Revelation 5:3 (ASV)

Εν (in) with locative (ουρανω), επ (upon) with genitive (γης), υποκατω (under) with ablative (γης), as in verse 13, including the whole universe, as in Ex 20:4 . The MSS. vary in the negative conjunctions after ουδεις (no one) between ουδε--ουδε (continuative, and not--nor) and ουτε--ουτε (disjunctive, neither--nor).

To look thereon (βλεπειν αυτο). Into the contents of the book. The universe declines the challenge.