Psalms 81:3

Our errand is, to give unto God the glory due unto his name, and in all our religious assemblies we must mind this as our business. In doing this we must eye God as our strength, and as the God of Jacob,

Blow up the trumpet in the new moon. Announce the sacred month, the beginning of months, when the Lord brought his people out of the house of bondage. Clear and shrill let the summons be which calls all Israel to adore the Redeeming Lord. In the time appointed, on our solemn feast day. Obedience is to direct our worship, not whim and sentiment: God's appointment gives a solemnity to rites and times which no ceremonial pomp or hierarchical ordinance could confer. The Jews not only observed the ordained month, but that part of the month which had been divinely set apart. The Lord's people in the olden time welcomed the times appointed for worship; let us feel the same exultation, and never speak of the Sabbath as though it could be other than "a delight" and "honourable." Those who plead this passage will keep such feasts as the Lord appoints, but not those which Rome or Canterbury may ordain.

Blow up the trumpet - שופר shophar, a species of horn. Certainly a wind instrument, as the two last were stringed instruments. Perhaps some chanted a psalm in recitativo, while all these instruments vere used as accompaniments. In a representative system of religion, such as the Jewish, there must have been much outside work, all emblematical of better things: no proof that such things should be continued under the Gospel dispensation, where outsides have disappeared, shadows flown away, and the substance alone is presented to the hearts of mankind. He must be ill off for proofs in iavour of instrumental music in the Church of Christ, who has recourse to practices under the Jewish ritual. The feast of the new moon was always proclaimed by sound of trumpet. Of the ceremonies on this occasion I have given a full account in my Discourse on the Eucharist. For want of astronomical knowledge, the poor Jews were put to sad shifts to know the real time of the new moon. They generally sent persons to the top of some hill or mountain about the time which, according to their supputations, the new moon should appear. The first who saw it was to give immediate notice to the Sanhedrin; they closely examined the reporter as to his credibility, and whether his information agreed with their calculations. If all was found satisfactory, the president proclaimed the new moon by shouting out מקדש mikkodesh! “It is consecrated.” This word was repeated twice aloud by the people; and was then proclaimed every where by blowing of horns, or what is called the sound of trumpets. Among the Hindoos some feasts are announced by the sound of the conch or sacred shell.

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 Jos 6:5; Lev 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 Isa 1:13; compare 2Ki 4:23; Amo 8:5; 1Ch 23:31; 2Ch 2:4. It is not certain, however, that the word used here means new moon. Prof. Alexander renders it in the month; that is, in the month, by way of eminence, in which the passover was celebrated. The word used - חדשׁ chôdesh - means, indeed, commonly the new moon; the day of the new moon; the first day of the lunar month Num 29:6; 1Sa 20:5, 1Sa 20:18, 1Sa 20:24; but it also means a month; that is, a lunar month, beginning at the new moon, Gen 8:5; Exo 13:4; et al. The corresponding or parallel word, as we shall see, which is rendered in our version, in the time appointed, means full moon; and the probability is, as Professor Alexander suggests, that in the beginning of the verse the month is mentioned in general, and the particular time of the month - the full moon - in the other part of the verse. Thus the language is applicable to the passover. On the other supposition - the supposition that the new moon and the full moon are both mentioned - there would be manifest confusion as to the time. In the time appointed - The word used here - כסה keseh - means properly the full moon; the time of the full moon. […]