2 Chronicles 35:16-19
16-19Everything went without a hitch in the worship of God that day as they celebrated the Passover and the offering of the Whole-Burnt-Offering on the Altar of God. It went just as Josiah had ordered. The Israelites celebrated the Passover, also known as the Feast of Unraised Bread, for seven days. The Passover hadn't been celebrated like this since the days of Samuel the prophet. None of the kings had done it. But Josiah, the priests, the Levites, all Judah and Israel who were there that week, plus the citizens of Jerusalem—they did it. In the eighteenth year of the rule of King Josiah, this Passover was celebrated.
20Some time later, after Josiah's reformation of The Temple, Neco king of Egypt marched out toward Carchemish on the Euphrates River on his way to war. Josiah went out to fight him.