…how much more shall your Father which is in heaven give good things to them that ask him? — Matthew 7:11
… how much more shall your heavenly Father give the Holy Spirit to them that ask him? — Luke 11:13
Philip Yancy
We pray for what God wants to give us, which may turn out to be good gifts or it may be the Holy Spirit. (From God’s viewpoint there is no better response to persistent prayer than the gift of the Holy Spirit, God’s own self.)
Like Peter, we may pray for food and get a lesson in racism; like Paul we may pray for healing and get humility.
We may ask for relief from trials and instead get patience to bear them.
We may pray for release from prison and instead get strength to redeem the time while there.
Asking, seeking, and knocking does have an effect on God, as Jesus insists, but it also has a lasting effect on the asker-seeker-knocker.
— Yancey, Philip (2008-09-02). Prayer (Kindle Locations 3330-3340). Zondervan. Kindle Edition.
“The real value of persistent prayer is not so much that we get what we want as that we become the person we should be.” 
Patrikin - Kinship through The Father 