A man asked the Messenger of Allah ﷺ, "Which aspect of Islam is best?"He replied, "That you feed others and offer greetings of peace to those you know and those you do not know."
أخبرنا قتيبة قال حدثنا الليث عن يزيد بن أبي حبيب عن أبي الخير
أن رجلا سأل رسول الله ﷺ أي الإسلام خير قال تطعم الطعام وتقرأ السلام على من عرفت ومن لم تعرف
Bukhari transmitted it, in Iman, chapter on spreading greetings being part of Islam, hadith no. 28, and Muslim, in Iman, chapter on explaining the varying degrees of Islam and which of its matters is best, hadith no. 39, both from Qutayba with this same chain.