R.C. Sproul, The Holiness of God (p. 276)

How can we love a holy God? The simplest answer I can give to this vital question is that we can't. Loving a holy God is beyond our moral power. The only kind of God we can love by our sinful nature is an unholy god, an idol made by our own hands.

Unless we are born of the Spirit of God, unless God sheds His holy love in our hearts, unless He stoops in His grace to change our hearts, we will not love Him... We can only love Him because He first loved us. To love a holy God requires grace, grace strong enough to pierce our hardened hearts and awaken our moribund souls.