If I shall forget thee, O Jerusalem! This confirms what was said in the former verse, and leaves us in no difficulty to understand what the Psalmist meant by it. For here God's people declare, and with the solemnity of an oath, that the remembrance of the holy city would be ever engra-yen upon their hearts, and never, under any circumstances, effaced. Having spoken of song, and of the instruments of music, the Psalmist's appeal is made in terms which corre-spond -- that his hand would forager its cunning, and his tongue cleave to his palate, or the roof of his mouth The meaning' is, that the Lord's people, while they mourn under personal trials, should be still more deeply affected by public calamities which befall the Church, it being' reasonable that the zeal of God's house should have the highest place in our hearts, and rise above all mere private considerations. The second part of the sixth verse some interpret -- If this be not my chief joy to see Jerusalem once more in a flourishing condition. Others -- Joy will never enter my heart more, till I be gladdened by the Church's restoration. Both meanings are in my opinion comprehended in the words of the Psalmist. The one cannot be separated from the other; for if we set Jerusalem above our chiefest joy, the height of this joy must arise from the consideration of its prosperity, and, if this be the case, the grief we feel under its calamities will be such as effectually to shut out all worldly joys.

If I forget thee, O Jerusalem - The meaning here is, that to sing in such circumstances would seem to imply that they had forgotten Jerusalem; that they were unmindful of its sorrows, and cared not that it was desolate. The remembrance of its calamities pressed hard upon them, and they could not do anything which would seem to imply that they had become unmindful of the sufferings that had come upon their nation. One will not make merry when a wife or child lies dying - or on the day of the funeral - or over the grave of a mother. A joyous and brilliant party, accompanied with music, feasting, dancing, when a friend has been just laid in the grave, when the calamities of war are abroad, when the pestilence is raging in a city, we feel to be untimely, unseemly, and incongruous. So these captives said it would be if they should make merry while their temple was in ruins; while their city was desolate; while their people were captives in a foreign land.
Let my right hand forget her cunning - Let my right hand forget its skill in music - all its skill. If I should now play on the harp - as indicative of joy - let the hand which would be employed in sweeping over its strings become paralyzed and powerless. Let the punishment come where it would seem to be deserved - on the hand which could play at such a time. So Cranmer held the hand which had been employed in signing a recantation of his faith in the fire, until it was burned off, and dropped in the flames.

If I forget thee, O Jerusalem - Such conduct would be, in effect, a renunciation of our land a tacit acknowledgment that we were reconciled to our bondage; a concession that we were pleased with our captivity, and could profane holy ordinances by using them as means of sport or pastime to the heathen. No: Jerusalem! we remember thee and thy Divine ordinances: and especially thy King and our God, whose indignation we must bear, because we have sinned against him.
Let my right hand forget - Let me forget the use of my right hand. Let me forget that which is dearest and most profitable to me; and let me lose my skill in the management of my harp, if I ever prostitute it to please the ungodly multitude or the enemies of my Creator!

(d) If I forget thee, O Jerusalem, let my right hand forget [her cunning].
(d) Even the faithful are touched by their particular griefs, yet the common sorrow of the Church is most grievous to them, and is such as they cannot but remember and lament.

If I forget thee, O Jerusalem,.... This was said by one or everyone of the Levites; or singers, as Aben Ezra and Kimchi; or by the congregation of Israel, as Jarchi; by one of them, in the name of the rest; or by the composer of the psalm. The Targum is,
"the voice of the Spirit of God answered and said, "if I forget", &c.''
that is, to weep over the calamities of Jerusalem; which might be thought, if the songs of Zion were sung; or to pray for the restoration of her prosperity and peace; as the church of Christ may be said to be forgotten, when men forget to mourn over its breaches, and show no concern for the reparation of them; or at the death of principal persons, which they lay not to heart; or at the great decay of religion in those that survive; or at the sins of professors, and their disregard to the word and ordinances: also when they forget to pray for her happiness in general; for the good of her members in particular; and especially for her ministers, that they may have assistance and success; and for a blessing on the word and ordinances, and for the conversion of sinners; and when they forget the worship of the Lord in it, and forsake the assembling of themselves together;
let my right hand forget her cunning; her skill in music, particularly in playing on the harp; see 1-Samuel 16:16; the harp was held in the left hand, and struck with the right; and that more softly or hardly, as the note required, in which was the skill or cunning of using it. Or let this befall me, should I so far forget Jerusalem as to strike the harp to one of the songs of Zion in a strange land: or let it forget any of its works; let it be disabled from working at all; let it be dry and withered, which, Aben Ezra says, is the sense of the word according to some; and Schultens (d), from the use of it in Arabic, renders it, let it be "disjointed", or the nerve loosened; see Job 31:22. Or the sense is, let everything that is as dear as my right hand he taken from me: or, as it may be rendered, "my right hand is forgotten" (e); that is, should I forget Jerusalem, it would; for that is as my right hand; so Arama. Some choose to translate the words thus, "may thou (O God) forget my right hand" (f); that is, to be at my right hand; to be a present help to me in time of need; to hold me by it, and to be the shade of it.
(d) Animadv. Philol. p. 181. (e) "oblita est nostra dextra", Castalio. (f) "Oblivisceris (O Domine) dexterae meae", Gejerus; so some in Michaelis.

What we love, we love to think of. Those that rejoice in God, for his sake make Jerusalem their joy. They stedfastly resolved to keep up this affection. When suffering, we should recollect with godly sorrow our forfeited mercies, and our sins by which we lost them. If temporal advantages ever render a profession, the worst calamity has befallen him. Far be it from us to avenge ourselves; we will leave it to Him who has said, Vengeance is mine. Those that are glad at calamities, especially at the calamities of Jerusalem, shall not go unpunished. We cannot pray for promised success to the church of God without looking to, though we do not utter a prayer for, the ruin of her enemies. But let us call to mind to whose grace and finished salvation alone it is, that we have any hopes of being brought home to the heavenly Jerusalem.

For joyful songs would imply forgetfulness of their desolated homes and fallen Church. The solemn imprecations on the hand and tongue, if thus forgetful, relate to the cunning or skill in playing, and the power of singing.