Part of the four small and wise, Proverbs 30:24–28.
Quick answer
The last of four, and it drops the pattern. No weakness is named. The creature simply holds on with its hands, and ends up somewhere no one would have let it in.
Read the whole unit
Four small creatures, each of which has what it needs without having what you would expect it to need.
Read the whole unit
This is the one numerical saying in the chapter that does not count three and then four. The others build tension by naming a smaller number first; this one simply says four, and gets on with it. Whatever the reason, the effect is that nothing is being saved for the end. All four items are equal.
The claim is in the header. These are קְטַנֵּי־אָרֶץ, the small of the earth, and they are חֲכָמִים מְחֻכָּמִים, a doubled form the NKJV renders exceedingly wise. The saying is not arguing that small things can be useful. It is arguing that wisdom and power have nothing to do with each other, and it proves it four times: not strong, yet provisioned; feeble, yet secure; no king, yet ordered; small enough to catch in a hand, yet living in a palace.
Three of the four are built the same way, with a lack stated and then overturned. The fourth breaks the pattern and states no lack at all, which leaves the list ending on an image rather than an argument.
And the placement is doing something. The man making this list opened the chapter by saying he was more stupid than any man. He is not writing from above these creatures. He put himself on the list before he made it.
What this verse contributes
The close, and the break in form. The three before it each named an absence and then overturned it. This one names no absence. It describes an ability, grasping, and then a location, and lets the gap between them do the work: the smallest thing on the list is in the grandest room on the list, and nobody decided to put it there.
The list therefore ends on the palace, which matters because the next saying ends on a king. Agur is drawing the two together: the king walks in with his troops, and the creature already inside got there with its hands.
Why translations differ
שְׂמָמִית occurs only here in the Hebrew Bible, and no one can be certain what animal it names. The NKJV prints spider and footnotes Or lizard, and other versions choose the lizard or the gecko, largely on the strength of the clinging described in the first line. The catalog reports the uncertainty and does not settle it, and the saying works either way.
From this side of the cross
Four creatures, and the thing they have in common is that none of them qualified. Wisdom in this passage is not a reward for capacity; it is simply present in things that have none, which is a strange thing to find near the end of a book about becoming wise. Paul says something a Christian will hear behind it, that God chose the weak things of the world to shame the mighty. Agur is not predicting Paul. He is noticing the same shape in the world that Paul later found in the gospel.
Related: 1 Corinthians 1:27 · Proverbs 30:24
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.