1 Samuel 18:4

Gave it to David. — It has been suggested that the reason of this gift was to enable his friend David — then poorly clad — to appear at his father’s court in a fitting dress; but this kind of present was usual among friends in those remote ages. Glaucus and Diomed, for instance, exchanged armour of a very different value.

“Now change we arms, and prove to either host
We guard the friendship of the line we boast.

* * * * * *

For Diomed’s brass arms, of mean device,
For which nine oxen paid (a vulgar price),
He gave his own of gold, divinely wrought:
A hundred beeves the shining purchase bought.”

Iliad, vi. 286–295.