The work of atonement derives from God's love; therefore it has not established the latter:
For this reason, Paul says that the love with which God embraced us "before the creation of the world" was established and grounded in Christ [Eph. 1:4-5]. These things are plain and in agreement with Scripture, and beautifully harmonize those passages in which it is said that God declared his love toward us in giving his only-begotten Son to die [John 3:16]; and, conversely, that God was our enemy before he was again made favourable to us by Christ's death [Rom. 5:10]. But to render these things more certain among those who require the testimony of the ancient church, I shall quote a passage of Augustine where the very thing is taught: "God's love," says he, "is incomprehensible and unchangeable. For it was not after we were reconciled to him through the blood of his Son that he began to love us. Rather, he has loved us before the world was created, that we also might be his sons along with his only-begotten Son - before we became anything at all. The fact that we were reconciled through Christ's death must not be understood as if his Son reconciled us to him that he might now begin to love those whom he hated. Rather, we have already been reconciled to him who loves us, with whom we were enemies on account of sin. The apostle will testify whether I am speaking the truth: 'God shows his love for us in that while we were yet sinners Christ died for us' [Rom. 5:8]. Therefore, he loved us even when we practiced enmity toward him and committed wickedness. Thus in a marvelous and divine way he loved us even when he hated us. For he hated us for what we were that he had not made; yet because our wickedness had not entirely consumed his handiwork, he knew how, at the same time, to hate in each one of us what we had made, and to love what he had made."
- John Calvin, Institutes 2.16.4