A.T. Robertson Commentary Revelation 10:10

"And I took the little book out of the angel`s hand, and ate it up; and it was in my mouth sweet as honey: and when I had eaten it, my belly was made bitter." — Revelation 10:10 (ASV)

I took--and ate it up (ελαβον--κα κατεφαγον αυτο). Second aorist active indicatives of the same verbs to show John's prompt obedience to the command. The order of the results is here changed to the actual experience (sweet in the mouth, bitter in the belly). The simplex verb εφαγον (I ate) is now used, not the compound κατεφαγον (I ate up).