"Bearding the lion”, as in “to confront danger head on” from I Samuel 17:35, when David rescues a lamb from a lion by holding the lion by his beard and slaying the lion.

The Hebrew does not use some hypothetical verb form of “beard” (zakan), but rather uses the Hebrew “to hold tightly”, so this English idiom is not from translating out of the Hebrew.  From where does “beard” have the verbal sense of “to hold by the beard”?

Reb Wlm

The OED describes the sense this way: “3. To oppose openly and resolutely, with daring or with effrontery; to set at defiance, thwart, affront. Esp. in fig. phr. to beard the lion in his den or lair. [Partly from the idea of taking a lion by the beard, partly from the use of beard as = face; see BEARD n. 1e.]”

The first citation (1525) refers to bearding Frenchmen; bearding lions doesn’t show up until 1749. 

The reference to the noun lists various phrases such as ”in spite of or maugre any one’s beard: in defiance of or direct opposition to his purpose. to one’s beard: to one’s face, openly. to be, meet, or run in any one’s beard: to oppose him openly and resolutely”.

The OED has this under beard, v, 3

3. To oppose openly and resolutely, with daring or with effrontery; to set at defiance, thwart, affront. Esp. in fig. phr. to beard the lion in his den or lair. [Partly from the idea of taking a lion by the beard, partly from the use of beard as = face; see BEARD n. 1e.]

Here are the first two cites:

1525 St. Papers Hen. VIII, VI. 454 If they [Frenchmen] be kept shorte, and berdyd, their stomakkis will soone wax more mylde. 1596 SHAKES. 1 Hen. VI, IV. i. 12 No man so potent breathes vpon the ground, But I will Beard him.

The first cite for beard the lion is surprisingly late:

1749 SMOLLETT Regicide II. vii. (1777) 39 Sooner would’st thou beard The lion in his rage.

I just knew I’d get pipped by Doc!

FWIW, the earlier (~1380) Wycliffe translation has:

35 Y pursuede, and killide hem, and rauyschide fro `the mouth of hem; and thei risiden ayens me, and I took the nether chaule `of hem, and Y stranglide, and killide hem.

I believe the Wycliffe is a translation of the Vulgate which has:

et sequebar eos et percutiebam eruebamque de ore eorum et illi consurgebant adversum me et adprehendebam mentum eorum et suffocabam interficiebamque eos

something like “I laid hold of(seized) their chin” - mentum is chin.