Anas bin Malik reported,

The Messenger of Allah ﷺ said, "When one of you is in prayer, he is in private conversation with his Lord . So let him not spit in front of him, nor to his right. Let him spit to his left, beneath his foot."

حدثنا بهز حدثنا شعبة عن قتادة

عن أنس

أن رسول الله ﷺ قال إذا كان أحدكم في صلاته فإنه يناجي ربه عز وجل فلا يتفلن بين يديه ولا عن يمينه وليتفل عن يساره تحت قدمه