It is narrated from Abu Sa'id al-Khudri (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) saw a man praying alone, and he (peace and blessings be upon him) said: "Is there anyone who will give charity to this man by praying along with him?"
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5007