The Emigrants said, "Messenger of Allah, we have never seen a people like those we have come to, more generous in sharing what little they have, more open-handed when they have much. They have spared us the burden of labor and given us a share in the harvest, so much so that we feared they would take all the reward for themselves."He replied, "No, not as long as you praise them and pray to Allah for them."
حدثنا يزيد أخبرنا حميد
قال المهاجرون يا رسول الله ما رأينا مثل قوم قدمنا عليهم أحسن مواساة في قليل ولا أحسن بذلا في كثير لقد كفونا المئونة وأشركونا في المهنإ حتى لقد حسبنا أن يذهبوا بالأجر كله قال لا ما أثنيتم عليهم ودعوتم الله عز وجل لهم
Its chain of transmission is sahih. It is found in Abu Dawud 4/255 no. 4812, in the book of Manners, on giving thanks for a kindness, Tirmidhi 4/153 no. 2487, in the description of the Resurrection, chapter 44, Ibn Abu Shayba 9/68 no. 6561, in the book of Manners, on good praise, Hakim 2/63, with Dhahabi concurring with him, and Bayhaqi 6/83, in the book of Gifts, on giving thanks for a kindness.