כִּ֗י אִם־בִּשְׁמֹנֶ֤ה עֶשְׂרֵה֙ שָׁנָ֔ה לַמֶּ֖לֶךְ יֹֽאשִׁיָּ֑הוּ נַעֲשָׂ֞ה הַפֶּ֧סַח הַזֶּ֛ה לַיהוָ֖ה בִּירוּשָׁלִָֽם׃
but in the eighteenth year of king Josiah was this passover kept to the LORD in Jerusalem.
Read halakhic rulings (Jewish law) on II Kings 23:23: and classical halakhic sources.