Schaff's Bible Dictionary
PRICKS, or GOADS, long, sharp-pointed sticks, which were used to drive cattle, etc., by pricking them. The expression in Acts 9:5 is a proverb, and originated in this - that restive oxen often push themselves or kick back against the goads, and thus wound themselves the more deeply. Hence the proverb is used to denote the folly and madness of resisting lawful authority. A great number of heathen writers use the proverb familiarly, and always to
signify the absurdity of such rebellion.