1867 304 "Blessed is the people that know the joyful sound; they shall walk, O Lord, in the light of thy countenance." (Psalm 89:15.) What is the joyful sound here spoken of? The Hebrew word is t'ruhah the sound of a trumpet. But not every sound of the trumpet was so called. To assemble the people to the door of the tabernacle of the congregation no such sound was required. The single blast for the princes to gather together was not this. To call Israel to their feasts and fasts the trumpet sounded, but not such a blast as is here referred to. But if the congregation, as they lay encamped in the wilderness, were to strike their tents, the camp to be broken up, and the people to keep close to the symbol of the divine presence, as it preceded the camps, or journeyed in their midst, then this special sound was heard. Also, if the land should be invaded, they were to sound the alarm, which seems to have partaken of the character of this sound, though the substantive, as in the previous case, is not expressed, but the verb from which it is derived.
Besides these special occasions, there were two regular times when the trumpet sound t'ruhah was heard: the one, the fiftieth year, on the tenth day of the seventh month, to proclaim the advent of the year of Jubilee (Lev. 25:9); the other, annually, on the first day of that same month, called the day of the trumpet-sound, or (as the Authorized Version) a day of blowing of trumpets (Num. 29:1) yom t'ruhah. This latter seems to elucidate what is spoken of in the Psalm.
It is not the announcement of the Jewish festivals in general as is often understood; for for them no such trumpet-blast was blown (see Num. 10:10 in the Hebrew). But the reference is surely to the first day of the seventh month, when, after a pause in their feasts since the day of Pentecost, the trumpet sounded to tell the people of the commencement of Tisri, in which the day of atonement and the feast of Tabernacles would be kept, and the year of Jubilee be from time to time proclaimed.
Looking at the Psalm from a dispensational point of view, this explanation will be found in character with the circumstances of the people in this, the third, book of Psalms. They are restored to their land, their captivity brought back (Psalm 85); the day of blowing of trumpets has had its fulfilment; they are gathered again round the centre God has appointed on earth, but the full blessing is not yet entered upon. For this the Psalmist by the spirit of prophecy pleads. His promises to David are unfulfilled. But, restored to their land, they plead for them, so can say, "Blessed is the people that know the joyful sound; they shall walk, O Lord, in the light of thy countenance."