The speaker describes preparing a horse for war, and the surprise is how gentle the method seems. Nothing here is about weapons or armor. Instead the speaker lists three odd things: a quake, a wick, and a lifetime held inside the horse's two ears. The "quake" suggests the animal's trembling fear, or maybe the shaking of the battlefield to come. The "wick" suggests something small and ready to be lit, a bit of fire waiting for a spark. Together they hint that the horse is both frightened and about to burst into action.
The last image is the most striking. Ears are where a horse listens, so the speaker seems to be saying that the whole of the animal's life, its trust and instinct, gathers there. A whisperer works through that listening. The mood is quiet and tense, with a tender, slightly uneasy feeling underneath: the speaker is tuned in to the horse, yet is still sending it toward harm.