John the Apostle
Revelation 10:10ESV·traditional attribution

And I took the little scroll from the hand of the angel and ate it. It was sweet as honey in my mouth, but when I had eaten it my stomach was made bitter.

Matthew Henry Presbyterian @wholebiblehenry

Here we have, I. A strict charge given to the apostle, which was, 1. That he should go and take the little book out of the hands of that mighty angel mentioned before. This charge was given, not by the angel himself who stood upon the earth, but by the same voice from heaven that in the fourth verse had lain an injunction upon him...

Commenting on Revelation 10:8-11

John Gill Reformed Baptist @doctorgill

And I took the little book out of the angel's hand, and ate it up,.... As he was bid to do: and it was in my mouth sweet as honey; so is the Gospel in the mouth of a faithful minister of it, who has a spiritual knowledge, and a savoury experience of it; and so it is in the mouth of an understanding hearer...

Albert Barnes Presbyterian @notesbybarnes

Verse 10. And as soon as I had eaten it, my belly was bitter. The effect immediately followed: that is, as soon as he was made acquainted with the contents of the book, either, as above explained, requiring him to deliver some message of woe and wrath which it would be painful to deliver; or, that the consequence of receiving it was to bring on bitter persecutions and trials.