The Messenger of Allah ﷺ said, "Hearts are vessels, and some are more retentive than others. So when you ask Allah , people, ask Him while being certain of His response, for Allah does not answer the supplication of a servant who calls upon Him from a heedless heart."
أن رسول الله ﷺ قال: القلوب أوعية وبعضها أوعى من بعض، فإذا سألتم الله عز وجل، أيها الناس، فاسألوه وأنتم موقنون بالإجابة، فإن الله لا يستجيب لعبد دعاه عن ظهر قلب غافل.
Ahmad (6655) narrated it from Hasan, who said, Ibn Lahia told us, Bakr bin Amr told us, from Abu Abdul-Rahman Hubli, from Abdullah bin Amr, who then mentioned it. Its chain includes Ibn Lahia, who has poor memory and about whom there is well-known discussion, as mentioned before, except that he did not err in this hadith because it has a basis. There is also a daif corroborating narration. Munziri graded it hasan in Targheeb (2571), as did Haythami in Majma (10/148).As for what is narrated from Abu Hurairah, who said that the Messenger of Allah ﷺ said, "Call upon Allah while being certain of a response, and know that Allah does not answer the prayer of a heedless, distracted heart," its chain is very daif. Tirmidhi (3479) narrated it, as did Ibn Hibban in his biography of Salih bin Bashir Marri in Majruheen (1/471), Ibn Adi in Kamil (4/1380), and Hakim (1/493), all of them through the route of Salih Marri, from Hisham bin Hassan, from Muhammad bin Sirin, from Abu Hurairah, who then mentioned it.Tirmidhi said, "This is a gharib hadith we do not know except through this route." As for Hakim, he said, "This is a hadith with a sound chain, narrated uniquely by Salih Marri, who was one of the ascetics of the people of Basra." Munziri responded to this, saying, "There is no doubt about Salih Marri's asceticism, but Abu Dawud and Nasai abandoned him." Targheeb wa Tarheeb (2572). Dhahabi likewise responded to this, saying, "I say, Salih is discarded."