The Messenger of Allah ﷺ said to me, "Worship Allah as though you see Him with your own eyes, for even if you do not see Him, He sees you. Perform your ablution thoroughly when you enter the mosque. Remember death during your prayer, for when a man remembers death in his prayer, he is bound to perform it well. Pray as a man who does not expect to pray any prayer after it. And beware of anything for which you would later have to apologize."
قال لي رسول الله ﷺ: اعمل الله رأي العين كأنك تراه، فإنك إن لم تكن تراه فإنه يراك، وأسبغ طهورك إذا دخلت المسجد، واذكر الموت في صلاتك، فإن الرجل يذكر الموت في صلاته لحري أن يحسن صلاته، وصل صلاة رجل لا يظن أن يصلي صلاة غيرها، وإياك وكل ما يعتذر منه.
No references are available.
Bayhaqi narrated it in Zuhd Kabir (527), and Daylami in Musnad Firdaws as mentioned by Sakhawi in Maqasid Hasanah (p.144, no. 275), and Diya Maqdisi in Mukhtarah (2199), all of them via Abu Asim Dahhak bin Makhlad, who said, Shabib bin Bishr narrated to us, who said, Anas bin Malik narrated to us, and he related it, except that Maqdisi confined himself to the last part of it. Its isnad is hasan because of Shabib bin Bishr, for his hadith is hasan. Ibn Hajar also graded it hasan, as Sakhawi reported from him.This hadith has corroborating narrations, but they are all defective.Tabarani narrated it in Kabir (6/54) from Muhammad bin Ishaq, who said, Abdullah bin Abu Bakr bin Muhammad bin Amr bin Hazm and Yahya bin Saeed bin Qays Ansari narrated to me that they both told him, from Saad bin Ammar, brother of Banu Saad bin Bakr, who was a companion, that a man said to him, "Advise me concerning myself, may Allah have mercy on you." He said, "When you stand for prayer, perform wudu thoroughly, for there is no prayer for one who has no wudu, and no faith for one who has no prayer." Then he said, "When you pray, pray as one bidding farewell, and give up seeking many of your needs, for that is present poverty. Gather together despair of what is in people's hands, for that is true wealth. And look at what you would need to excuse yourself for, in word or deed, and avoid it."Its narrators are trustworthy, except that it stops at the companion.