The opening summons to praise takes us far away from the solitary wrestlings and communings in former psalms. Now
"The singers lift up their voice, And the trumpets make endeavour, Sounding, 'In God rejoice! In Him rejoice for ever!'"
But the clear recognition of purity as the condition of access to God speaks in this invocation as distinctly as in any of the preceding. "The righteous" whose lives conform to the Divine will, and only they can shout aloud their joy in Jehovah. Praise fits and adorns the lips of the "upright" only, whose spirits are without twist of self-will and sin. The direction of character expressed in the word is horizontal rather than vertical, and is better represented by "straight" than "upright." Praise gilds the gold of purity and adds grace even to the beauty of holiness. Experts tell us that the _kinnor_ (harp, A.V. and R.V.) and _nebel_ (psaltery) were both stringed instruments, differing in the position of the sounding board, which was below in the former and above in the latter, and also in the covering of the strings (_v._ Delitzsch, Eng. transl. of latest ed., I. 7, n.). The "new song" is not necessarily the psalm itself, but may mean other thanksgivings evoked by God's meditated-on goodness. But, in any case, it is noteworthy that the occasions of the new song are very old acts, stretching back to the first creation and continued down through the ages. The psalm has no trace of special recent mercies, but to the devout soul the old deeds are never antiquated, and each new meditation on them breaks into new praise. So inexhaustible is the theme that all generations take it up in turn, and find "songs unheard" and "sweeter" with which to celebrate it. Each new rising of the old sun brings music from the lips of Memnon, as he sits fronting the east. The facts of revelation must be sung by each age and soul for itself, and the glowing strains grow cold and archaic, while the ancient mercies which they magnify live on bright and young. There is always room for a fresh voice to praise the old gospel, the old creation, the old providence.
This new song is saturated with reminiscences of old ones, and deals with familiar thoughts which have come to the psalmist with fresh power. He magnifies the moral attributes manifested in God's self-revelation, His creative Word, and His providential government. "The word of Jehovah," in ver. 4, is to be taken in the wide sense of every utterance of His thought or will ("non accipi pro doctrina, sed pro mundi gubernandi ratione," Calvin). It underlies His "works," as is more largely declared in the following verses. It is "upright," the same word as in ver. 1, and here equivalent to the general idea of morally perfect. The acts which flow from it are "in faithfulness," correspond to and keep His word. The perfect word and works have for source the deep heart of Jehovah, which loves "righteousness and judgment," and therefore speaks and acts in accordance with these. Therefore the outcome of all is a world full of God's loving-kindness. The psalmist has won that "serene and blessed mood" in which the problem of life seems easy, and all harsh and gloomy thoughts have melted out of the sky. There is but one omnipotent Will at work everywhere, and that is a Will whose law for itself is the love of righteousness and truth. The majestic simplicity and universality of the cause are answered by the simplicity and universality of the result, the flooding of the whole world with blessing. Many another psalm shows how hard it is to maintain such a faith in the face of the terrible miseries of men, and the more complex "civilisation" becomes, the harder it grows; but it is well to hear sometimes the one clear note of gladness without its chord of melancholy.