This is from Dreisbach and Hall, The Sacred Rights of Conscience. I don't know how it can be proven Otis wrote this, but it is Calvinist to the core, even giving the Holy Spirit authority over repentance. Maybe Percy Morton wrote it.
A proclamation for a public thanksgiving
[T]he wise and holy Governor of the world has, in his righteousness providence, sent droughts into this colony...we have the greatest reasons to adore and praise the Supreme Disposer of all events, who deals infinitely better with us than we deserve, and amidst all his judgments hath remembered mercy...affording to an ungrateful people...comforts of life...that he would pour his Spirit upon all orders of men...and bring us to a hearty repentance and reformation and purify all his churches and make ours Emmanuel's land; that he would spread the knowledge of the Redeemer throughout the whole earth and fill the world with his glory.
Given under our hands, at the Council-Chamber at Watertown, the fourth day of November, in the year of our Lord one thousand seven hundred and seventy-five.
By their Honors' command
James Otis. Percy Morton, Dep Secy.
God Save The People!