The meaning of this verse is obscure, partly from its abrupt brevity, and partly from the ambiguity of one word. The word springs is, beyond all controversy, to be here taken metaphorically; but interpreters are not agreed as to the explanation of the metaphor. Some understand it as denoting hopes, some affections, and others thoughts. Did the idiom of the language admit, I would willingly subscribe to the opinion of those who translate it melodies or songs. But as this might be considered unsupported by the usage of the Hebrew term, I am rather inclined to adopt, as most suitable to the subject in hand, the opinion that lookings is the proper translation, the root of the word signifying an eye. It is as if the Psalmist had said, I will always be earnestly looking, as it were, with fixed eyes upon thee. Let us now inquire what is meant by the other clause, The singers as the players upon instruments. This, it is true, is an abrupt form of expression; but the sense, about which there is a general agreement, is, that so great will be the ground for rejoicing, that the praises of God will resound in Zion continually, with the energy of the living voice, as well as with musical instruments. This, then, is a confirmation of what was spoken before concerning the glorious restoration of Zion; for by the greatness of the joy, and the manifold harmony and melody of praises, is portrayed the happiness which shall prevail in the midst of it. At the same time, we have here described the great design of all the gifts which God has conferred upon his Church with so liberal a hand; namely, that the faithful, by hymns and songs, should testify their remembrance of his benefits and gratefully acknowledge them. [1] The Hebrew word chvllym, cholelim, which we have rendered the players upon instruments, is translated by some, those who dance to the sound of instruments. But this is a matter of no great importance, it being enough to consider the meaning, in short, as this, that there will be a continual concert of God's praises in the Church, where he unfolds the treasures of his grace, and that the faithful will be heard singing successively and in response. Moreover, the prophet shows his singular love to the Church, and the singular care and zeal which he exercised about her, to encourage and stir up all the godly, by his example, to cultivate and manifest the same zeal, agreeably to what is stated in another psalm, "If I forget thee, O Jerusalem! let my right hand forget her cunning. If I do not remember thee, let my tongue cleave to the roof of my mouth; if I prefer not Jerusalem above my chief joy." (Psalm 137:5) All our affections are then settled on the Church, when, gathered in from the vague and vain objects by which they are distracted, and regarding with indifference the honors, pleasures, riches, and pageantries of the world, they find enough to engage and satisfy them in the spiritual glory of Christ's kingdom, and in that alone.

Footnotes

1 - Cresswell connects the second clause of this verse with the first, in this manner: -- "Singers also, and players upon the pipe, shall chant, All my wells are in thee;'" i.e., says he, "all my sources of refreshment, of hope, and of salvation, are in thee, O Zion!" He adds, "The phrase, wells of salvation, occurs in Isaiah 12:3, the Hebrew word being the same as that which, in our two English versions of the Psalms, is translated springs and fountains." Walford connects the two clauses in the same manner, "They sing with musical instruments, All my springs are in thee.'" "The persons who are here said to sing," he observes, "accompanied by musical instruments, are the people spoken of in verse 6. They are described as uniting in a joyful song of praise and thanksgiving; and the burden of their song is, All my springs are in thee.' Springs or fountains are a constant image for the blessings which are productive of refreshment and happiness. These new-born converts are, therefore, represented as joining the universal Church, and offering ascriptions of praise to God, who is the overflowing source of all the streams of good, which refresh and bless the people."

As well the singers as the players on instruments shall be there - literally, "The singers as the players on instruments." The image is that of a musical procession, where the singers go before, followed by those who play on various instruments of music. The idea seems to be that when the number of the true friends of God shall be made up, or shall all be enrolled, there will be a triumphal procession; or, they are seen by the psalmist, moving before God as in a triumphal procession. Compare the notes at Isaiah 35:10. Perhaps the reference is to heaven - the true Zion; to the assembling of all who shall have been born in Zion, and who shall have become citizens of the true Zion, the Jerusalem above.
All my springs are in thee - The word rendered springs means properly a place of fountains (see the notes at Psalm 84:6), and also a fountain, Genesis 7:11; Genesis 8:2. It thus becomes an emblem of happiness; of delight; of pleasure; and the ideal here is that the highest happiness of the psalmist was found in what is here referred to by the word "thee." That word may refer either to God or to Zion; but as the subject of the psalm is Zion, it is most natural to suppose that the reference is to that. Thus it accords with the sentiment so often found in the Psalm, where the writer expresses his love for Zion; his pleasure in its solemnities; his desire to abide there as his permanent home. Compare Psalm 23:6; Psalm 84:2-4, Psalm 84:10. The idea has been beautifully expressed by Dr. Dwight, in his version of Psalm 137:6 :
"I love thy church, O God;
Her walls before thee stand,
Dear as the apple of thine eye,
And graven on thy hand.
"If e'er my heart forget
Her welfare or her woe,
Let every joy this heart forsake,
And every grief o'erflow.
"Beyond my highest joy
I prize her heavenly ways.
Her sweet communion, solemn vows,
Her hymns of love and praise."

As well the singers, etc. - Perhaps, this may mean no more than, The burden of the songs of all the singers and choristers shall be, "All my fountains (ancestors and posterity) are in thee;" and consequently, entitled to all thy privileges and immunities. Instead of שרים sharim, "singers," many MSS. and early printed editions have, sarim, "princes." Some for מעיני mayenai, "my fountains," would read with several of the Versions, מעוני meoney, "habitations;" but no MS. yet discovered supports this reading.
It would be a very natural cause of exultation, when considering the great privileges of this royal city, to know that all his friends, family, and children, were citizens of this city, were entered in God's register, and were entitled to his protection and favor. Applied to the Christian Church, the privileges are still higher: born of God, enrolled among the living in Jerusalem, having their hearts purified by faith, and being washed and made clean through the blood of the covenant, and sealed by the Holy Spirit of promise, such have a right to the inheritance among the saints in light. I need not add that springs, wells, fountains, and cisterns, and waters are used metaphorically in the sacred writings for children, posterity, fruitful women, people, etc.; see among others Proverbs 5:15, Proverbs 5:16; Psalm 68:26; Isaiah 48:1; and Revelation 17:15. The old Psalter understands the whole as relating to Gospel times; and interprets it accordingly. Bishop Horne takes it in the same sense. The whole Psalm is obscure and difficult. I will venture a literal version of the whole, with a few explanatory interpolations, instead of notes, in order to cast a little more light upon it.
1. A Psalm to be sung by the posterity of Korah. A prophetic song.
2. "Jehovah loves his foundation, the city built by him on holy mountains. He loves the gates of Zion more than all the habitations of Jacob."
3. "Honorable things are declared of thee, O city of God. Selah."
4. "I will number Egypt and Babylon among my worshippers; behold Philistia and Tyre! They shall be born in the same place." They shall be considered as born in the city of God.
5. "But of Zion it shall be said, This one, and that one," persons of different nations, "was born in it, and the Most High shall establish it."
6. "Jehovah shall reckon in the registers of the people, This one was born there."
7. "The people shall sing, as in leading up a choir, All my fountains," the springs of my happiness, "are in thee."
I have nearly followed here the version of Mr. N. M. Berlin, who wonders that there should be any doubt concerning this translation of the last verse, when Symmachus and Aguila, who must have well known the sense of the Masoretic text, have translated: Και ᾳδοντης ῳς χοροι πασαι πηγαι εν σοι· "And they shall sing, as in leading up a dance, All my fountains are in thee." The translation cannot be far from the meaning.

As well the singers as the players on instruments [shall be there]: all my (g) springs [are] in thee.
(g) The prophet sets his whole affections and comfort in the church.

As well the singers as the players on the instruments shall be there,.... In Zion, in the church; signifying that there should be great spiritual joy there when the above things should be accomplished; great joy in the churches, because of the conversion of Jews and Gentiles; and great joy in the persons themselves, born again, and brought to Zion; in allusion to the vocal and instrumental music used in the temple service; see Isaiah 35:10.
all my springs are in thee; which are either the words of the psalmist, or rather of the souls born in Zion; who, in their spiritual songs, will thus express themselves concerning the church, in which are the word and ordinances, compared to fountains of living water, and are springs of spiritual peace and refreshment to converted persons; see Joel 3:18, where also the Spirit and his graces are communicated by the ministry of the word and ordinances in the church, which are signified by wells and rivers of living water, John 4:14 and particularly here stands Christ, the fountain of gardens, and well of living waters, for the supply and comfort of saints, and his blood a fountain opened for cleansing and purification, Song 4:15, yea, here flows the river of God's love, the streams whereof make glad the city of God; and which, like the waters in Ezekiel's vision, come from under the threshold of the sanctuary, Psalm 46:4 or the words may be considered as an address of the psalmist, or of the church, or of regenerate persons, unto Christ:
all my springs or fountains are in thee; the fulness of grace dwells in him, the springs of all joy, and peace, and comfort, are with him; the wells of salvation are in him, and both grace and glory are from him; he is the spring of all grace now, and the fountain of all happiness hereafter. Gussetius (z) has a very peculiar version of the whole text, which he renders thus
"all my fountains will be singing in thee, or of thee, as those that dance at the sound of the pipe:''
taking the allusion to be to the playing of fountains in gardens, and to the delightful sound the waters make; but the accents will not admit of such a sense.
(z) Comment. Ebr. p. 845.

As in a great procession of those thus written up, or registered, seeking Zion (Isaiah 2:3; Jeremiah 50:5), "the singers" and "players," or pipers, shall precede.
all my springs--So each shall say, "All my sources of spiritual joy are in Thee" (Psalm 46:4; Psalm 84:6).

Singers - There shall be great rejoicing and praising God, both with vocal and instrumental musick, for this glorious work of the conversion of the Gentiles. He describe's evangelical worship, by legal phrases and customs, as the prophets frequently do. In thee - In Zion or the church. These words may be here added as the burden of the song, which these singers are supposed to have sung, in the name of all the people of God. All our desires and delights are in thee, all the springs of mercy, grace, and glory, flow to us only in and thro' thee.