Jami` at-Tirmidhi 1967
Abu  Shuraih Al-'Adawf said:
"My eyes saw the Messenger of Allah, and my ears  heard him speaking when he was speaking and he said: 'Whoever believes in Allah and the Last Day, then let him honor his guest with his reward.' They said: 'What is the reward?' He said: ' A day and a night.' He said: 'And hospitality is for three days, whatever is beyond that is charity. And whoever believes in Allah and the Last Day, then let him say what is good or keep silent."
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا اللَّيْثُ بْنُ سَعْدٍ، عَنْ سَعِيدِ بْنِ أَبِي سَعِيدٍ الْمَقْبُرِيِّ، عَنْ أَبِي شُرَيْحٍ الْعَدَوِيِّ، أَنَّهُ قَالَ أَبْصَرَتْ عَيْنَاىَ رَسُولَ اللَّهِ صلى الله عليه وسلم وَسَمِعَتْهُ أُذُنَاىَ حِينَ تَكَلَّمَ بِهِ قَالَ ‏"‏ مَنْ كَانَ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ فَلْيُكْرِمْ ضَيْفَهُ جَائِزَتَهُ ‏"‏ ‏.‏ قَالُوا وَمَا جَائِزَتُهُ قَالَ ‏"‏ يَوْمٌ وَلَيْلَةٌ وَالضِّيَافَةُ ثَلاَثَةُ أَيَّامٍ وَمَا كَانَ بَعْدَ ذَلِكَ فَهُوَ صَدَقَةٌ وَمَنْ كَانَ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ فَلْيَقُلْ خَيْرًا أَوْ لِيَسْكُتْ ‏"‏ ‏.‏ قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ ‏.‏