Ps 80, which looks back into the time of the leading forth out of Egypt, is followed by another with the very same Asaphic thoroughly characteristic feature of a retrospective glance at Israel’s early history (cf. More particularly Psa 81:11 with Psa 80:9). In Psalms 81 the lyric element of Ps 77 is combined with the didactic element of Ps 78. The unity of these Psalms is indubitable. All three have towards the close the appearance of being fragmentary. Fro the author delights to ascend to the height of his subject and to go down into the depth of it, without returning to the point from which he started. In Ps 77 Israel as a whole was called “the sons of Jacob and Joseph;” in Ps 78 we read “the sons of Ephraim” instead of the whole nation; here it is briefly called “Joseph.” This also indicates the one author. Then Psalms 81, exactly like Psa 79:1-13, is based upon the Pentateuchal history in Exodus and Deuteronomy. Jahve Himself speaks through the mouth of the poet, as He did once through the mouth of Moses - Asaph is κατ ̓ ἐξοχήν the prophet (חזה) among the psalmists. The transition from one form of speech to another which accompanies the rapid alternation of feelings, what the Arabs call talwı̂n el - chitab, “a colouring of a speech by a change of the persons,” is also characteristic of him, as later on of Micah (e.g., Mic 6:15.).
This Psalms 81 is according to ancient custom the Jewish New Year’s Psalm, the Psalm of the Feast of Trumpets (Num 29:1), therefore the Psalm of the first (and second) of Tishri; it is, however, a question whether the blowing of the horn (shophar) at the new moon, which it calls upon them to do, does not rather apply to the first of Nisan, to the ecclesiastical New Year. In the weekly liturgy of the Temple it was the Psalm for the Thursday.
The poet calls upon them to give a jubilant welcome to the approaching festive season, and in Psa 81:7. Jahve Himself makes Himself heard as the Preacher of the festival. He reminds those now living of His loving-kindness towards ancient Israel, and admonishes them not to incur the guilt of like unfaithfulness, in order that they may not lose the like tokens of His loving-kindness. What festive season is it? Either the Feast of the Passover or the Feast of Tabernacles; for it must be one of these two feasts which begin on the day of the full moon. Because it is one having reference to the redemption of Israel out of Egypt, the Targum, Talmud (more particularly Rosh ha - Shana, where this Psalm is much discussed), Midrash, and Sohar understand the Feast of Tabernacles; because Psa 81:2-4 seem to refer to the new moon of the seventh month, which is celebrated before the other new moons (Num 10:10), as יום התּרוּעה (Num 29:1, cf. Lev 23:24), i.e., to the first of Tishri, the civil New Year; and the blowing of horns at the New Year, is, certainly not according to Scripture, but yet according to tradition (vid., Maimonides, Hilchoth Shophar Psa 1:2), a very ancient arrangement. Nevertheless we must give up this reference of the Psalm to the first of Tishri and to the Feast of Tabernacles, which begins with the fifteenth of Tishri: - (1) Because between the high feast-day of the first of Tishri and the Feast of Tabernacles on the fifteenth to the twenty-first (twenty-second) of Tishri lies the great day of Atonement on the tenth of Tishri, which would be ignored, by greeting the festive season with a joyful noise from the first of Tishri forthwith to the fifteenth. (2) Because the remembrance of the redemption of Israel clings far more characteristically to the Feast of the Passover than to the Feast of Tabernacles. This latter appears in the oldest law-giving (Exo 23:16; Exo 34:22) as חג האסיף, i.e., as a feast of the ingathering of the autumn fruits, and therefore as the closing festival of the whole harvest; it does not receive the historical reference to the journey through the desert, and therewith its character of a feast of booths or arbours, until the addition in Lev 23:39-44, having reference to the carrying out of the celebration of the feasts in Canaan; whereas the feast which begins with the full moon of Nisan has, it is true, not been entirely free of all reference to agriculture, but from the very beginning bears the historical names פּסח and חג המּצּות. (3) Because in the Psalm itself, viz., in Psa 81:6, allusion is made to the fact which the Passover commemorates.
Concerning על־הגּתּית vid., on Psa 8:1. The symmetrical, stichic plan of the Psalm is clear: the schema is 11. 12. 12.