Atharva Veda 2.27: A charm against an opponent in debate

Let not the enemy win the cause! Strong and predominant art thou.
Refute mine adversary's speech. Render them dull and flat, O Plant.

The strong-winged bird discovered thee, the boar unearthed thee with his snout.
Refute mine adversary's speech. Render them dull and flat, O Plant.

Yea, Indra laid thee on his arm, to cast the Asuras to the ground.
Refute mine adversary's speech. Render them dull and flat, O Plant.

Indra devoured the Pātā plant that he might lay the Asuras low.
Refute mine adversary's speech! Render them dull and flat, O Plant.

With this I overcome my foes as Indra overcame the wolves.
Refute mine adversary's speech! Render them dull and flat, O Plant.

O Rudra, Lord of Healing Balms, dark-crested, skilful in thy work!— Refute mine adversary's speech. Render them dull and flat, O Plant.

Indra, defeat the speech of him who meets us with hostility.
Comfort us with thy power and might. Make me superior in debate.