John Gill Bible Commentary

If I do not remember thee,.... In prayer, in discourse, in conversation; this is the same as before, to forget, repeated for the confirmation of it; let my tongue cleave to the roof of my mouth; as is the case of a person in a fever, or in a violent thirst, which is to be in great distress, Psa 18:6; the sense is, let me have no use of my tongue; let me be dumb and speechless, and never sing a song or speak a word more, should I be so forgetful of the deplorable state of Jerusalem as to sing songs at such a season, and in an enemy's country; if I prefer not Jerusalem above my chief joy; meaning not God his exceeding joy, Psa 43:4; as his Creator, preserver, and benefactor, and much less as his covenant God and Father; as having loved him with an everlasting love; as the God of all grace unto him, and as his portion and exceeding great reward: nor Christ, the object of joy unspeakable and full of glory; joy in the greatness, glory, and fulness of his person; in the blessings and promises of his grace; in what he has done and suffered; as risen, ascended, exalted, and who will come a second time: nor the joy of the Holy Ghost in a way of believing, and in hope of the glory of God; but all worldly joy, or matter of it; and this not in things sinful, nor merely such as worldlings have in the increase of their substance; but a lawful joy, such as in the health, happiness, and prosperity of a man's family, wife, and children, and his own; which is the greatest outward joy a man can have; and yet the church of God and interest of Christ are preferred by a good man to these; see Sa1 4:19; which appears when all a man has that is matter of joy is sacrificed for the public good and interest of religion; when he can take no comfort in any outward enjoyment because of the sad case of Zion, Mal 2:3; when joy for its good is uppermost, and is first in his thoughts and words; when this is the "head" or "beginning" (g) of his joy, as it may be rendered. So Pindar (h) calls the chief, principal, and greatest part of joy, , the beginning of joy, the top and perfection of it. (g) "caput laetitiae meae", Musculus, Junius & Tremellius, Piscator, Gejerus. (h) Pythia, Ode 1. v. 4.