Grace - unconditional or undeserved?

Grace is not unconditional acceptance, but it is undeserved. That is a very difficult balance to strike! God's grace comes to us without prerequisites, finding us as we are. God's grace does not  come to the "deserving" (there is no such person), and it does not discriminate. Rather, initially it comes to us freely. But once it enters into our lives, God's grace demands changes; it holds us accountable. Why? Grace demands our holiness and growth for our sake as well as for God's glory.  Grace intercepts destructive behavior, protects us from the ravages of sin, sanctifies us so we can be "holy" and "happy", two inseparable qualities.

Ministries of Mercy, Timothy J. Keller, P&R Publishing, 1997, pp. 226-227.