Having resolved, what ought to be resolved, hold on to it till you have succeeded. Having desired what ought to be desired, hold on to it till your desire is fulfilled. Having asked what ought to be asked, do not leave the hold till you get it. Having thought what ought to be thought, hold on to it till you have succeeded. With heart mellowed, the Lord must yield to your wishes or forgetting yourself, you should ask Him with all your heart. Persevere, be tenacious and never give up, for it is the quality of a Devotee never to retreat, abandoning his resolve.
(From : Sai Veda, The Word of God, sayings of Bhagavan Sri Sathya Sai Baba)