Jabir ibn Sulaim reported: I saw a man whose opinion was followed by everyone and no one would contradict what he said. I asked who he was and I was told he was the Messenger of Allah, peace and blessings be upon him. I said to him twice, “Upon you be peace, O Messenger of Allah.” The Prophet said, “Do not say upon you be peace, for that is the greeting for the dead in the time of ignorance. Rather say peace be upon you.” I asked, “Are you the Messenger of Allah?” The Prophet said, “I am the Messenger of Allah, Allah who will remove your affliction when you are distressed and you call upon him, who will cause food to grow for you when you are starving and call to him, who will restore your lost animal in the desert when you call upon him.” I said, “Give me instructions.” The Prophet said, “Do not abuse anyone.” I have not abused anyone since, neither a freeman, nor a slave, nor a camel, nor a sheep. The Prophet said, “Do not hold in contempt a small act of goodness, because even speaking to your brother with a cheerful face is an act of goodness. Hold up your lower garment halfway to the leg and at least above the ankles, for trailing it is arrogance and Allah dislikes pride. If a man disparages you because of bad qualities he knows you have, then do not disparage him for the bad qualities you know he has. Verily, he will only earn the consequences of his abuse.”

Source: Sunan Abu Dawud 4084

Grade: Sahih (authentic) according to Ibn Hajar

عَنْ أَبِي جُرَيٍّ جَابِرِ بْنِ سُلَيْمٍ قَالَ رَأَيْتُ رَجُلًا يَصْدُرُ النَّاسُ عَنْ رَأْيِهِ لَا يَقُولُ شَيْئًا إِلَّا صَدَرُوا عَنْهُ قُلْتُ مَنْ هَذَا قَالُوا هَذَا رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قُلْتُ عَلَيْكَ السَّلَامُ يَا رَسُولَ اللَّهِ مَرَّتَيْنِ قَالَ لَا تَقُلْ عَلَيْكَ السَّلَامُ فَإِنَّ عَلَيْكَ السَّلَامُ تَحِيَّةُ الْمَيِّتِ قُلْ السَّلَامُ عَلَيْكَ قَالَ قُلْتُ أَنْتَ رَسُولُ اللَّهِ قَالَ أَنَا رَسُولُ اللَّهِ الَّذِي إِذَا أَصَابَكَ ضُرٌّ فَدَعَوْتَهُ كَشَفَهُ عَنْكَ وَإِنْ أَصَابَكَ عَامُ سَنَةٍ فَدَعَوْتَهُ أَنْبَتَهَا لَكَ وَإِذَا كُنْتَ بِأَرْضٍ قَفْرَاءَ أَوْ فَلَاةٍ فَضَلَّتْ رَاحِلَتُكَ فَدَعَوْتَهُ رَدَّهَا عَلَيْكَ قَالَ قُلْتُ اعْهَدْ إِلَيَّ قَالَ لَا تَسُبَّنَّ أَحَدًا قَالَ فَمَا سَبَبْتُ بَعْدَهُ حُرًّا وَلَا عَبْدًا وَلَا بَعِيرًا وَلَا شَاةً قَالَ وَلَا تَحْقِرَنَّ شَيْئًا مِنْ الْمَعْرُوفِ وَأَنْ تُكَلِّمَ أَخَاكَ وَأَنْتَ مُنْبَسِطٌ إِلَيْهِ وَجْهُكَ إِنَّ ذَلِكَ مِنْ الْمَعْرُوفِ وَارْفَعْ إِزَارَكَ إِلَى نِصْفِ السَّاقِ فَإِنْ أَبَيْتَ فَإِلَى الْكَعْبَيْنِ وَإِيَّاكَ وَإِسْبَالَ الْإِزَارِ فَإِنَّهَا مِنْ الْمَخِيلَةِ وَإِنَّ اللَّهَ لَا يُحِبُّ الْمَخِيلَةَ وَإِنْ امْرُؤٌ شَتَمَكَ وَعَيَّرَكَ بِمَا يَعْلَمُ فِيكَ فَلَا تُعَيِّرْهُ بِمَا تَعْلَمُ فِيهِ فَإِنَّمَا وَبَالُ ذَلِكَ عَلَيْهِ

4084 سنن أبي داود كِتَاب اللِّبَاسِ لا تقل عليك السلام فإن عليك السلام تحية الميت قل السلام عليك

المحدث ابن حجر العسقلاني خلاصة حكم المحدث صحيح

http://dailyhadith.abuaminaelias.com/2013/07/21/hadith-on-abuse-do-not-disparage-someone-who-abuses-you-for-he-will-be-punished-in-the-hereafter/