Like the interlude between the 6th and 7th seal, Chapters 10 and 11 is an interlude between the 6th and the 7th trumpet. In Chapter 10 we have the renewal of John's call to prophesy. Remember that the role of the prophet was not necessarily to predict the future (that is a very modern understanding) the prophet's role was to speak for God. This speaking for God was called forth-telling (as opposed to foretelling which would be predicting the future). In Biblical times this forth-telling often contained conditional predictions of the future (and some that were unconditional). The prophet's role was to tell what God gave him/her to tell. John is to take the scroll and eat it and then continue to speak the vision God has given him.
Notice that the "mighty angel" is standing with one foot on the sea and the other on dry land -- his posture encompasses all of creation and what he speaks will be a judgement on all of creation. In Revelation 6:10 the martyrs cried "how long" until they would be avenged. The mighty angel's role is to answer that question and to announce "there will be no more delay, (10:6). The seventh trumpet announces the final judgment.
The account draws its imagery from Ezekiel 2 where Ezekiel is called to prophecy and is given a scroll with writing on both sides. Here John eats the scroll. It is sweet like honey in his mouth, just as the Word of God is sweet to the believer. For those who belong to God, God's word is never judgment but is always grace and peace and life. However, for the unbeliever the Word of God contains much that challenges behavior, activity and attitudes and can be "difficult to swallow." Will I follow my own will into continued rebellion or will I align my life with the purposes of God. The image of consuming the scroll is a great image for preachers. As a preacher the Word of God must be born in us -- we must consume it, digest it before we can effectively teach and preach it. It is another way of saying that all Christian preaching is incarnational: the word must be born in the life and soul of the preacher before it an be fully realized in the congregation.
The final analysis is that John must continue his work and to "prophesy about many peoples, nations and languages and kings (10:11)."
The interlude will continue in chapter 11.