The Prophet says, that he was set by God as a watchtower, which was also fortified, that he might observe the wickedness of the people. In order to gain more authority for his prophecy, he introduces God as the speaker. He had spoken hitherto in his own person; but now God himself comes forth, and says, I have made thee a citadel. Jerome renders the last word “probation.” The verb בחן, becken, means to prove; and Jeremiah uses the verb in this verse, “that thou mayest prove their way.” But as the word מבצר, mebezar, “fortress, “follows, we cannot take the word here otherwise than as meaning a citadel or rampart. I therefore have no doubt but that a citadel for watching is what is meant; as though God had said, that his Prophet was like a watchtower, from which might be seen at one glance whatever was done far and wide: for we cannot see far from a plain, but they who are located high can see to a great distance.

But the word fortress is also added: for it behooved Jeremiah to watch without fear, and not to be exposed to the threats, calumnies, or clamors of the people. Jeremiah intimates that two things are required in God’s servants, even knowledge and undaunted courage; for it was not enough for the prophets to see clearly what was needful, except they were firmly prepared to discharge their office. Both these things seem to be included, when he says, that he was set as a watchtower, and also as a fortress

Why was he thus set? That thou mayest know, he says, and prove their way Let us now see what was the intention of this. The Prophet no doubt here claims power and credit to himself, that he might not only freely but authoritatively reprove the people: for objections, we know, were ever in their mouths, that they might be at liberty to despise the Prophet’s teaching, as though it did not proceed from God. This then was the reason why God here declares that Jeremiah was like a citadel, and that a fortified one; he was made so, that he might observe and know the way of the people. Hence it followed, that however obstinately they might defend themselves, it availed them nothing; for Jeremiah was endued with the highest authority, even that which was divine, in order to perform his office of a judge in condemning them: for it immediately follows —