Abu Ayyub reported: A man came to the Prophet, peace and blessings be upon him, and he said, “O Messenger of Allah, teach me something and make it concise.” The Prophet said, “When you stand to pray, then pray as if it were a farewell prayer. Do not say anything for which you must apologize and do not hope to acquire what other people have.”
Source: Sunan Ibn Majah 4171
Grade: Hasan (fair) according to Al-Albani
عَنْ أَبِي أَيُّوبَ قَالَ جَاءَ رَجُلٌ إِلَى النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ يَا رَسُولَ اللَّهِ عَلِّمْنِي وَأَوْجِزْ قَالَ إِذَا قُمْتَ فِي صَلَاتِكَ فَصَلِّ صَلَاةَ مُوَدِّعٍ وَلَا تَكَلَّمْ بِكَلَامٍ تَعْتَذِرُ مِنْهُ وَأَجْمِعْ الْيَأْسَ عَمَّا فِي أَيْدِي النَّاسِ
4171 سنن ابن ماجه كتاب الزهد باب الحكمة
المحدث الألباني خلاصة حكم المحدث حسن
Source: Daily Hadith