Adam Clarke on Jonah 3:2

And preach unto it the preaching - וקרא את הקריאה vekera eth hakkeriah, "And cry the cry that I bid thee." Be my herald, and faithfully deliver my message. The word κηρυξ in Greek answers to the Hebrew קורא kore: both signifying a crier, a herald, a preacher; one that makes proclamation with a loud and earnest cry. Such was John Baptist, Isa 40:3; such was Jesus Christ, John 7:18-37; and such were all his apostles. And such earnestness becomes a ministry that has to do with immortal souls, asleep and dead in sin, hanging on the brink of perdition, and insensible of their state. The soft-speaking, gentle-toned, unmoved preacher, is never likely to awaken souls. As we preach, so the people hear; scarcely receiving any counsels that appear to have no importance by the manner in which they are delivered. But this earnestness is widely different from that noisy, blustering, screaming rant, that manifests more of the turbulence of disorderly passions, than of the real inspired influence of the Spirit of God.