In the father's response to his two sons in the parable, we see God's compassion for his people. Likewise, as we approach him in prayer, he welcomes us with joy.
God has given us the "privilege of causality". To put it more simply: Something does change when we pray.
The Psalms remind us that there is more than one way to pray and invite us to walk with them on the first steps of a journey into an authentic relationship with God.
Trying to get the mechanics of prayer right can keep us from the most important aspect: coming with an open heart before God.
We are invited to enter into prayer in the same way as a loving parent invites his or her child to come.