Sahih al-Bukhari 531
Narrated Anas:
The Prophet (ﷺ) said, "Whenever anyone of you offers his prayer he is speaking in private to his Lord. So 
he should not spit to his right but under his left foot." Qatada said, "He should not spit in front of him 
but to his left or under his feet." And Shu`ba said, "He should not spit in front of him, nor to his right 
but to his left or under his foot." Anas said: The Prophet (ﷺ) said, "He should neither spit in the direction 
of his Qibla nor to his right but to his left or under his foot."
حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا هِشَامٌ، عَنْ قَتَادَةَ، عَنْ أَنَسٍ، قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم ‏"‏ إِنَّ أَحَدَكُمْ إِذَا صَلَّى يُنَاجِي رَبَّهُ فَلاَ يَتْفِلَنَّ عَنْ يَمِينِهِ، وَلَكِنْ تَحْتَ قَدَمِهِ الْيُسْرَى ‏"‏‏.‏ وَقَالَ سَعِيدٌ عَنْ قَتَادَةَ لاَ يَتْفِلُ قُدَّامَهُ أَوْ بَيْنَ يَدَيْهِ، وَلَكِنْ عَنْ يَسَارِهِ أَوْ تَحْتَ قَدَمَيْهِ‏.‏ وَقَالَ شُعْبَةُ لاَ يَبْزُقُ بَيْنَ يَدَيْهِ وَلاَ عَنْ يَمِينِهِ، وَلَكِنْ عَنْ يَسَارِهِ أَوْ تَحْتَ قَدَمِهِ‏.‏ وَقَالَ حُمَيْدٌ عَنْ أَنَسٍ عَنِ النَّبِيِّ صلى الله عليه وسلم ‏"‏ لاَ يَبْزُقْ فِي الْقِبْلَةِ وَلاَ عَنْ يَمِينِهِ، وَلَكِنْ عَنْ يَسَارِهِ أَوْ تَحْتَ قَدَمِهِ ‏"‏‏.‏