6 The love, therefore, wherewith God loveth, is incomprehensible and immutable. For it was not from the time that we were reconciled unto Him by the blood of His Son that He began to love us; but He did so before the foundation of the world, that we also might be His sons along with His Only-begotten, before as yet we had any existence of our own. Let not the fact, then, of our having been reconciled unto God through the death of His Son be so listened to or so understood, as if the Son reconciled us to Him in this respect, that He now began to love those whom He formerly hated, in the same way as enemy is reconciled to enemy, so that thereafter they become friends, and mutual love takes the place of their mutual hatred; but we were reconciled unto Him who already loved us, but with whom we were at enmity because of our sin. Whether I say the truth on this, let the apostle testify, when he says: “God commendeth His love toward us, in that, while we were yet sinners, Christ died for us.” Rom. v. 8, 9. He, therefore, had love toward us even when we were practising enmity against Him and working iniquity; and yet to Him it is said with perfect truth, “Thou hatest, O Lord, all workers of iniquity.” Ps. v. 5. Accordingly, in a wonderful and divine manner, even when He hated us, He loved us; for He hated us, in so far as we were not what He Himself had made; and because our own iniquity had not in every part consumed His work, He knew at once both how, in each of us, to hate what we had done, and to love what He had done. And this, indeed, may be understood in the case of all regarding Him to whom it is truly said, “Thou hatest nothing that Thou hast made.” Wisd. xi. 25. For He would never have wished anything that He hated to exist, nor would aught that the Omnipotent had not wished exist at all, were it not that in what He hated there was also something that He loved. For He justly hateth and reprobateth vice as utterly repugnant to the principle of His procedure, yet He loveth even in the persons of the vitiated what is susceptible either of His own beneficence through healing, or of His judgment by condemnation. In this way God at the same time hateth nothing of what He has made; for as the Creator of natures, and not of vices, it was not He who made the evil that He hateth; and of these same evils, all is good that He really doeth, either by mercifully healing them, or by judicially regulating them. Seeing, then, that He hateth nothing that He hath made, who can worthily describe how much He loveth the members of His Only-begotten, and how much more the Only-begotten Himself, in whom are hid all things visible and invisible, which were ordained in their various classes, and which He loves in fullest harmony with such ordination? For the members of His Only-begotten He is leading on by the liberality of His grace to an equality with the holy angels; while the Only-begotten Himself, being Lord of all, is doubtless Lord of angels, being by nature, as God, the equal not of angels, but rather of the Father Himself; while through grace, in respect of which He is man, how can He otherwise than surpass all angelic excellence, seeing that in Him human flesh and the Word constitute but one personality?
See where John Calvin references this quote in the Institutes here