Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates this statement of the Prophet (peace and blessings be upon him): "When a person stands to perform prayer, he should not spit in front of him because as long as he is engaged in prayer, he is supplicating before his Lord. He should also not spit to his right side because there is an angel on his right. He should spit to his left side or beneath his foot and bury it."
Hadith Referenceصحیح ابن حبان / كتاب الصلاة / 2269
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «الصحيحة» (3973): ق.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرطهما، إسحاق بن إبراهيم: هو ابن راهويه.