Isaiah 60:19 - Matthew Poole's English Annotations on the Holy Bible

The sun shall be no more thy light, & c.; these shall not be at all esteemed in comparison of the spiritual light of the church; and this is laid down as the assurance of the church's comfort, as the former was for her safety, so that God will not only be a shield, but a sun to her, Psalms 84:11; not that they shall not have the sun and moon among them, but that the light of the godly, as such, should principally consist in what is spiritual. The Lord shall be unto thee an everlasting light; Christ shall scatter all darkness and ignorance, enlightening thee with the doctrines of the gospel, and graces of his Spirit; and this shall be everlasting, not wax and wane, and suffer eclipses and settings, as the sun and moon do, but it shall be constant, without shadow of change; no night; which will be undoubtedly true of the church in heaven, whatever it will be, or how near soever it will come to it, here, which I presume will bear its analogy. Thy God thy glory; always ministering matter of thy glorying in him; or, thy interest in this God shall be great honour to thee; or else it is the same thing with the sentence immediately before in other words, that will make time glorious, a metonymy of the efficient; thus he is said to give glory, Psalms 84:11.