Proverbs 30:19 (BSB)

the way of an eagle in the sky, the way of a snake on a rock, the way of a ship at sea, and the way of a man with a maiden.

From Proverbs 30. Also in the ESV.

Commentary on Proverbs 30:19

• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on Proverbs 30:18-23: Here is, I. An account of four things that are unsearchable, too wonderful to be fully known. And here, 1. The first three are natural things, and are only designed as comparisons for the illustration of the last. We cannot trace, (1.) An eagle in the air.
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on Proverbs 30:19: The way of an eagle in the air,.... And so of any other bird; but this is mentioned, because it flies swiftest, and soars highest: but the way in which it goes is not known, nor can it be seen with the eye; it cuts the air, and passes through it, but leaves no track behind it which may be pointed to, and it may...
• Keil & Delitzsch (Lutheran), Biblical Commentary on the Old Testament on Proverbs 30:18-20: Pro 30:18-20 The following proverb, again a numerical proverb, begins with the eagle, mentioned in the last line of the foregoing: 18 Three things lie beyond me, And four I understand not: 19 The way of the eagle in the heavens, The way of a serpent over a rock, The way of a ship on the high sea, And the way of a man with a maid.