Verse 3 "Upon an instrument of ten strings, and upon the psaltery: upon the harp with a solemn sound." There was a "glare", if I may so put it, which characterised the divine appointments of Judaism. An august temple, ornamented with gold and silver; precious stones, golden candlesticks, golden alter, priests in rich attire, trumpets, cymbals, harps – all of which were adapted to an age when the church was in a state of infancy. But, when the "substance" is come, it is time that the "shadows" flee away. The best exposition of "harps" etc. in singing, is given by Dr Watts –
"Oh may my heart in tune be found,
Like David's harp of solemn sound."
Verse 4. "For thou, Lord, hast made me glad through thy work." It was natural for the psalmist to sing because he was glad; and to sing unto the Lord, because his gladness was caused by a contemplation of the divine work. If we consider either creation or providence, we shall find overflowing reasons for joy. But when we come to review the work of redemption, gladness knows no bounds, but feels that she must praise the Lord with all her might. There are times when in the contemplation of redeeming love we feel that if we did not sing we must die; silence would be as horrible to us as if we were gagged by inquisitors, or stifled by murderers.
Verse 5 "O Lord, how great are thy works! and thy thoughts are very deep." Verily, my brethren, there is no sea so deep as those thoughts of God where – "the wicked flourish," and "to good suffer." There is nothing so profound, nothing so deep as that. And dost thou wish to cross this depth? Then, remove not from clinging to the wood of Christ's cross, and thou shalt not sink; hold fast to Christ alone.
Verse 6 "A brutish man knoweth not; neither doth a fool understand this." In this and the following verses the effect of the psalm is heightened by contrast; the shadows are thrown in to bring out the lights more prominently. What a stoop from the preceding verse; from the saint to the brute, from the worshipper to the boor, from the psalmist to the fool! Yet, alas, the character described here is not an uncommon one. ... A man must either be a saint or a brute, he has no other choice. His type must be the adoring seraph, or the ungrateful swine, ... O God, how sorrowful a thing it is that men whom thou hast so largely gifted, and made in thine own image, should so brutify themselves that they will neither see nor understand what thou hast made so clear. Well might an eccentric writer say, "God made man a little lower than the angels at first, and he has been trying to get lower ever since."
Verses 12-15 "The righteous shall flourish. ..."
David here tells us how the righteous man shall flourish. He shall flourish "like the palm tree; he shall grow like a cedar in Lebanon." He has just said that the "wicked" spring up like the grass. What a contrast, then, this picture of the evergreen and durable palm and cedars.
He tells us where he shall flourish. "Those that be planted in the house of the Lord shall flourish in the courts of our God." Within the sanctuary of the Church of God we have the communion of saints. There our fellowship is with the Father, and with His Son Jesus Christ. There are dispensed the ordinances of our religion, and the word of truth. There God commandeth the blessing, even life for evermore.
He also tells us when he shall flourish. "They shall bring forth fruit in old age." This is to show the "permanency" of their principle of life, and to distinguish them from natural productions.
He also tells us why he shall flourish. "They shall be fat and flourishing; to show that the Lord is upright." We might have supposed that they would flourish to show that they were upright. But, it is by the grace of God that they are what they are – not they, but the grace of God which is in them. From Him is their fruit found. Their preservation and fertility are to the praise and glory of God. What He does for them He has engaged to do, to show that He is upright.