John Trapp on Esther 9:20

Verſe 20. And Mordecai wrote theſe things] He wrote with authority as a Magiſtrate (ſay ſome) that the Jewes ſhould keep theſe dayes with greateſt ſolemnitie. He wrote the relation of theſe things before-mentioned, ſay others, as the ground of this annual feſtivitie. Or elſe it may be meant more generally, that Mordecai was the Pen-man of the Holy Ghoſt, in writing this whole book of Eſther; as was before hinted.

And ſent letters unto all the Jewes, — both night and farre] Propinquis & longinquis, that they might all agree together about the time and manner of praiſing God: and ſo ſing the great Hallelujah. See, 2 Cor. 1.11. 2 Chron. 20.26, 27, 28. Pſal. 124.1, 2. and 126.1. Pſal. 136. penned for a recorded publike forme, to praiſe God among the multitude, Pſal. 109.20. and in the great Congregation, Pſal. 22.22, 25. David would go into the preſſes of people, and there praiſe the Lord, Pſal. 116.18, 19. This was to walk worthy of the Lord, Col. 1.10. This was to make a proportionable return, for we are Gods ſoile, and our thanks his crop.