Then I took the little book out of the angel’s hand and ate it, and it was as sweet as honey in my mouth. But when I had eaten it, my stomach became bitter.
Revelation 10:10

It has happened in most families’ experience—a toddler consumes way more candy than a parent would have allowed. And the aftermath results in a sour stomach or worse.

In the apostle John’s vision in Revelation, the angel that held a scroll told John to consume the scroll—but with a warning: It would be sweet to the taste but sour to the stomach. While the Word of God is always sweet to the taste (Psalm 119:103), its contents can sometimes be troubling. Such would be the contents of the scroll John would consume, for it foretold trouble and suffering that would come upon the earth. But whether the subject is blessing or trouble, all of the Word of God must be consumed and applied. We are to preach not only the parts of the Bible that are sweet to the taste but also the parts that trouble the soul.

Let us imitate the Berean Christians—they searched the Scriptures daily to glean their truths and apply them to their lives (Acts 17:11).

Any part of the Bible can only be properly explained in reference to the whole Bible.
F. F. Bruce