1. Exposition

Why are there seven seals?

Revelation 5:1 (ESV)

1 Then I saw in the right hand of him who was seated on the throne a scroll written within and on the back, sealed with seven seals.

This could speak to the size of this scroll, indicating that it was so large that it needed seven strings (and hence seals) to hold it together. Seven is also a full number, indicating total security in relation to the contents of this scroll. The latter is the better understanding.