Jeremiah 25:3

We read, Jeremiah 1:2, that Jeremiah began to prophesy in the thirteenth year of Josiah. Josiah reigned thirty-one years, 2 Kings 22:1; so that taking in the thirteenth year, Jeremiah prophesied nineteen years during the life of Josiah, to which adding the four of Jehoiakim's reign, it maketh twenty-three. These twenty-three years, saith the prophet, I have been a preacher to you, and I have not been negligent in my work; but like men that get up early in the morning to despatch their business, so have I been in the discharge of my prophetical office.