At times it is as if the prayer is not being accepted; there is one thing that can be done on such occasions. One should ask some very pious person to pray and then he himself should pray to God that He may hear the prayer of that pious person. It has been observed quite often that the prayer has been accepted in this way. I have experienced it myself and it has been happening in the case of many people before me, as well. It is said that once Bawa Ghulam Farid fell ill; he prayed for his recovery but the prayer was not accepted. Then he asked one of his disciples to pray for him—this disciple was a very pious person (He was either Sheikh Nizamuddin or Khawaja Qutbud Din). His prayer was also not accepted. He, then prayed to God very fervently and asked Him to raise that disciple of his to the rank where the prayers are very often accepted. Next morning he told the disciple that he had prayed for him for a higher rank. When the disciple heard this, he was very much moved and he started praying for him very fervently—so fervently that it was accepted and Bawa Ghulam Farid recovered from his illness.
(Malfoozat Vol. 9, pg. 234)