“The love of God is immutable, unalterable, and invariable; it is like himself, “the same today, yesterday, and for ever”: and, indeed, God is love; it is his nature; it is himself; and therefore must be without any variableness, or shadow of turning. It admits of no distinctions, by which it appears to alter and vary. Some talk of a love of benevolence, by which God wishes or wills good to men; and then comes on a love of beneficence, and he does good to them, and works good in them: and then a love of complacency and delight takes place, and not till then. But this is to make God changeable, as we are: the love of God admits of no degrees, it neither increases nor decreases; it is the same from the instant in eternity it was, without any change: it is needless to ask whether it is the same before as after conversion, since there were as great, if not greater gifts of love, bestowed on the object loved, before conversion, as after; such as the gift of God himself, in the everlasting covenant; the gift of his Son to die for them when in their sins; and the gift of the Spirit to them, in order to regenerate, quicken, and convert them; heaven itself, eternal life, is not a greater gift than these; and yet they were all before conversion. There never were any stops, lets, or impediments to this love; not the fall of Adam, nor the sad effects of it; nor the actual sins and transgressions of God’s people, in a state of nature; nor all their backslidings, after called by grace; for still he loves them freely, (Hosea 14:4) for God foreknew that they would fall in Adam, with others, that they would be transgressors from the womb, and do as evil as they could; yet this hindered not his taking up thoughts of love towards them, his choice of them, and covenant with them. Conversion makes a change in them; brings them from the power of Satan to God, from darkness to light, from bondage to liberty; from fellowship with evil men to communion with God: but it makes no change in the love of God; God changes his dispensations and dealings with them, but never changes his love; he sometimes rebukes and chastises them, but still he loves them; he sometimes hides his face from them, but his love continues the same, (Ps. 89:29-33; Isa. 54:7-10) the manifestations of his love are various; to some they are greater, to others less; and so to the same persons, at different times; but love in his own heart is invariable and unchangeable.
The love of God endures for ever; it is an everlasting love, in that sense, (Jer. 31:3) it is the bond of union between God and Christ, and the elect; and it can never be dissolved; nothing can separate it, nor separate from it (Rom. 8:35, 38, 39). The union it is the bond of, is next to that, and like it, which is between the three divine persons (John 17:21, 23). The union between soul and body, may be, and is dissolved, at death; but neither death nor life can separate from this; this lovingkindness of God never departs; though health, and wealth, and friends, and life itself may depart, this never will, (Isa. 54:10) whatever God takes away, as all the said things may be taken away by him, he will never take away this, (Ps. 89:33) having loved his own which were in the world, he loves them to the end, to the end of their lives, to the end of time, and to all eternity (John 13:1).” – John Gill (source)