Albert Barnes Commentary 2 Samuel 1:21

"Ye mountains of Gilboa, Let there be no dew nor rain upon you, neither fields of offerings: For there the shield of the mighty was vilely cast away, The shield of Saul, not anointed with oil." — 2 Samuel 1:21 (ASV)

Let there be no dew ... - For a similar passionate form of poetic malediction, compare Job 3:3-10 and Jeremiah 20:14-18.

Nor fields of offerings - He calls down a curse of such complete barrenness on the soil of Gilboa that not even enough will grow for an offering of first-fruits. The latter part of the verse is better translated this way: For there the shield of the mighty was polluted, the shield of Saul was not anointed with oil, but with blood. Shields were usually anointed with oil in preparation for battle (Isaiah 21:5).