According to the author of the book, Agur, there are three or four things in the world that are so amazing and mysterious that he cannot understand them. It's like when you see something cool, but you don't know how it works or why it happens; it just makes you say, "Wow!"
Proverbs 30:18: There be three [things which] are too wonderful for me, yea, four which I know not:
Contradicts the concept of wonder and mystery by emphasizing God's wisdom as hidden and preordained, suggesting nothing is truly unknowable.
1 Corinthians 2:7: But we speak the wisdom of God in a mystery, [even] the hidden [wisdom], which God ordained before the world unto our glory: