“Therefore goe thou and reade in the roule, which thou hast written from my mouth, the wordes of the Lord in the eares of the people in the Lords house vpon the fasting day: and also thou shalt reade them in the eares of all Iudah, that come out of their cities.”
1611 King James Version (KJV)
36:6 Upon the fasting day - It was undoubtedly, because of the concourse of people which the prophet knew would that day be in the temple, that he chose that day, when some would be present from all parts of Judah.