Psalms 81:3

“Blow up the trumpet in the new moon, etc.] Either in every new moon, or first day of the month, which was religiously observed by the Jews, (<120423>2 Kings 4:23) or rather the new moon, or first day of the seventh month, the month Tisri, which day was a memorial of blowing of trumpets, (<032334>Leviticus 23:34), and so the Targum, “blow the trumpet in the month of Tisri,” when their new year began, and was typical of the year of the redeemed of the Lord, of the acceptable year of our God, of the famous new year, the Gospel dispensation, when old things passed away, and all things became new. The Jews say this blowing of trumpets was in commemoration of Isaac’s deliverance, a ram being…”

“Blow up the trumpet - The word rendered blow means to make a clangor or noise as on a trumpet. The trumpet was, like the timbrel, the harp, and the psaltery, a common instrument of music, and was employed on all their festive occasions. It was at first made of horn, and then was made similar in shape to a horn. Compare Joshua 6:5; Leviticus 25:9; Job 39:25. In the new moon - On the festival held at the time of the new moon. There was a high festival on the appearance of the new moon in the month of Tisri, or October, which was the beginning of their civil year, and it is not improbable that the return of each new moon was celebrated with special services. See the notes at Isaiah 1:13;…”

“81:3 The ram’s horn mustered armies and announced special holy days (47:5; 98:6). • new moon: The first day of the lunar month marked a festival.”

“Blow: Psa 98:6; Num 10:1-9; Ch1 15:24, Ch1 16:6, Ch1 16:42; Ch2 5:12, Ch2 13:12, Ch2 13:14 new: Lev 23:24, Lev 23:25; Num 10:10, Num 28:11; Kg2 4:23; Col 2:16 solemn: Num 15:3; Deu 16:15; Ch2 2:4, Ch2 8:13; Lam 2:6; Nah 1:15 Psalms 81:5”