Mishkat al-Masabih 39
Abu Huraira said:
We were seated around God's messenger, Abu Bakr, ‘Umar and some others being with us, when God's messenger got up and left us. He delayed for some time, which made us fear that he might be attacked by some enemy when we were not with him; so being alarmed we got up. I was the first to be alarmed. I therefore went out to look for God's messenger and came to a garden belonging to the B. an-Najjar, a section of the Ansar, I went round it looking for a gate, but failed to find one. Seeing a rabi’ (i.e. a streamlet) flowing into the garden from a well outside, I drew myself together and went in to where God's messenger was. He said, “Is it Abu Huraira?" I replied, “Yes, messenger of God." He said, “What do you want?" I replied, “You were among us, but got up and went away and delayed for a time, so fearing that you might be attacked by some enemy when we were not with you, we became alarmed. I was the first to be alarmed, so when I came to this garden I drew myself together as a fox does; and these people are following me." Addressing me by name he gave me his sandals and said, “Take away these sandals of mine, and when you meet anyone outside this garden who testifies that there is no god but God, being assured of it in his heart, gladden him by announcing that he will go to paradise." Now the first one I met was ‘Umar. He asked, “What are these sandals, Abu Huraira?” and I replied, “These are God’s messenger’s sandals with which he has sent me to gladden anyone I met who testified that there is no god but God, being assured of it in his heart, with the announcement that he would go to paradise.” Thereupon ‘Umar struck me on the breast and I fell down on my seat.” He then said, “Go back, Abu Huraira”; so I went back to God’s messenger, and I was ready to weep. ‘Umar followed me closely, and there he was behind me. God’s messenger said, “What is the matter with you, Abu Huraira?” I replied, “I met ‘Umar and conveyed to him your message, whereupon he gave me a blow on the breast which made me fall down on my seat and ordered me to go back.” God’s messenger said, “What induced you, ‘Umar, to do what you did?” He replied, “Messenger of God, for whom I would give my father and mother as ransom, did you send Abu Huraira with your sandals to gladden anyone he met who testified that there is no god but God, being assured of it in his heart, with the announcement that he would go to paradise?” He said, “Yes.” ‘Umar said, “You must not do it, for I am afraid that people will trust in it alone; let them go on doing [good] works.” God’s messenger said, “Well let them.” 

Muslim transmitted it.
وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: كُنَّا قُعُودًا حَوْلَ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَعنا أَبُو بَكْرٍ وَعُمَرُ رَضِيَ اللَّهُ عَنْهُمَا فِي نَفَرٍ فَقَامَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مِنْ بَيْنَ أَظْهُرِنَا فَأَبْطَأَ عَلَيْنَا وَخَشِيَنَا أَنْ يُقْتَطَعَ دُونَنَا وَفَزِعْنَا فَقُمْنَا فَكُنْتُ أَوَّلَ مَنْ فَزِعَ فَخَرَجْتُ أَبْتَغِي رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ حَتَّى أَتَيْتُ حَائِطًا لِلْأَنْصَارِ لِبَنِي النَّجَّارِ فَدُرْتُ بِهِ هَلْ أَجِدُ لَهُ بَابًا فَلَمْ أَجِدْ فَإِذَا رَبِيعٌ يَدْخُلُ فِي جَوْفِ حَائِطٍ مِنْ بِئْرٍ خَارِجَةٍ وَالرَّبِيعُ الْجَدْوَلُ فاحتفزت كَمَا يحتفز الثَّعْلَب فَدَخَلْتُ عَلَى رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ أَبُو هُرَيْرَةَ فَقُلْتُ نَعَمْ يَا رَسُولَ اللَّهِ قَالَ مَا شَأْنُكَ قُلْتُ كُنْتَ بَيْنَ أَظْهُرِنَا فَقُمْتَ فَأَبْطَأْتَ عَلَيْنَا فَخَشِينَا أَنْ تُقْتَطَعَ دُونَنَا فَفَزِعْنَا فَكُنْتُ أَوَّلَ مَنْ فَزِعَ فَأَتَيْتُ هَذَا الْحَائِطَ فَاحْتَفَزْتُ كَمَا يَحْتَفِزُ الثَّعْلَبُ وَهَؤُلَاء النَّاس ورائي فَقَالَ يَا أَبَا هُرَيْرَة وَأَعْطَانِي نَعْلَيْه قَالَ اذْهَبْ بنعلي هَاتين فَمن لقِيت من وَرَاء هَذَا الْحَائِط يَشْهَدُ أَنْ لَا إِلَهَ إِلَّا اللَّهُ مُسْتَيْقِنًا بِهَا قَلْبُهُ فَبَشِّرْهُ بِالْجَنَّةِ فَكَانَ أَوَّلُ مَنْ لَقِيتُ عُمَرَ فَقَالَ مَا هَاتَانِ النَّعْلَانِ يَا أَبَا هُرَيْرَة فَقلت هَاتَانِ نَعْلَا رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بَعَثَنِي بِهِمَا مَنْ لَقِيتُ يَشْهَدُ أَنْ لَا إِلَهَ إِلَّا اللَّهُ مُسْتَيْقِنًا بِهَا قَلْبُهُ بَشرته بِالْجنَّةِ فَضرب عمر بِيَدِهِ بَيْنَ ثَدْيَيَّ فَخَرَرْتُ لِاسْتِي فَقَالَ ارْجِعْ يَا أَبَا هُرَيْرَةَ فَرَجَعْتُ إِلَى رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فأجهشت بكاء وركبني عمر فَإِذا هُوَ على أثري فَقَالَ لِي رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَا لَك يَا أَبَا هُرَيْرَة قلت لقِيت عمر فَأَخْبَرته بِالَّذِي بعثتني بِهِ فَضرب بَين ثديي فَخَرَرْت لاستي قَالَ ارْجع فَقَالَ لَهُ رَسُول الله يَا عُمَرُ مَا حَمَلَكَ عَلَى مَا فَعَلْتَ قَالَ يَا رَسُولَ اللَّهِ بِأَبِي أَنْتَ وَأُمِّي أَبَعَثْتَ أَبَا هُرَيْرَةَ بِنَعْلَيْكَ مَنْ لَقِيَ يَشْهَدُ أَنْ لَا إِلَهَ إِلَّا اللَّهُ مُسْتَيْقِنًا بِهَا قَلْبُهُ بَشَّرَهُ بِالْجَنَّةِ قَالَ نَعَمْ قَالَ فَلَا تَفْعَلْ فَإِنِّي أَخْشَى أَنْ يَتَّكِلَ النَّاسُ عَلَيْهَا فخلهم يعْملُونَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فخلهم ". رَوَاهُ مُسلم