Revelation 5:5 provides the answer to the angel's question: the Lion of Judah has conquered and is worthy to open the scroll.

In Revelation 5:9, the Lamb is declared worthy to open the scroll — directly answering the angel's question here.

In Revelation 4:11, the elders declare God worthy of glory for creation — setting the theme of worthiness that the angel's question about the scroll invokes.

In Isaiah 29:11, a sealed scroll that no one can read prefigures the sealed scroll here that no one is worthy to open.

In John 10:15, Jesus lays down his life for the sheep — the basis for his worthiness to open the scroll as the slain Lamb.

In Isaiah 41:22, false gods are challenged to declare the future — only the worthy one here can reveal the scroll's future events.