'Shield' in the Bible

Ye mountains of Gilboa, let there be no dew, neither let there be rain, upon you, nor fields of offerings: for there the shield of the mighty is vilely cast away, the shield of Saul, as though he had not been anointed with oil.

The God of my rock; in him will I trust: he is my shield, and the horn of my salvation, my high tower, and my refuge, my saviour; thou savest me from violence.

Thou hast also given me the shield of thy salvation: and thy gentleness hath made me great.