“Children come into the world in a condition of complete dependence.  They cannot operate as self-sufficient, independent agents unless their parents give up much of their own independence and freedom for years.  If you don’t allow your children to hinder your freedom in work and play at all, and if you only get to your children when it doesn’t inconvenience you, your children will grow up physically only.  In all sorts of other ways they will remain emotionally needy, troubled, and over-dependent.  The choice is clear.  You can either sacrifice your freedom or theirs.  It’s them or you.  To love your children well, you must decease that they may increase.  You must be willing to enter into the dependency they have so eventually they can experience the freedom and independence you have.

All life-changing love toward people with serious needs is a substitutional sacrifice.  If you become personally involved with them, in some way, their weaknesses flow toward you as your strengths flow toward them.  As John Stott says, substitution is at the heart of Christianity: the essence of sin is we humans substituting ourselves for God, while the essence of salvation is God substituting himself for us.  We put ourselves where only God deserves to be; God puts himself where we deserve to be” (2 Corinthians 5:21).”

-Tim Keller, The Reason for God.