It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever among you has the door of supplication opened for him (by being granted the ability to supplicate), the doors of Paradise have been opened for him. And Allah Almighty has not been asked for anything more beloved to Him than being asked for well-being (al-'afiyah)." This hadith is sahih al-isnad (its chain is authentic), but the two Shaykhs (Bukhari and Muslim) did not record it.