Someone who cannot repay someone should make supplication

Al-Adab Al-Mufrad · Book 10 · Hadith 217

حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، قَالَ‏:‏ حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ ثَابِتٍ، عَنْ أَنَسٍ، أَنَّ الْمُهَاجِرِينَ قَالُوا‏:‏ يَا رَسُولَ اللهِ، ذَهَبَ الأَنْصَارُ بِالأَجْرِ كُلِّهِ‏؟‏ قَالَ‏:‏ لاَ، مَا دَعَوْتُمُ اللَّهَ لَهُمْ، وَأَثْنَيْتُمْ عَلَيْهِمْ بِهِ‏.‏

Anas reported that the Muhajirun said, "Messenger of Allah, the Ansar have taken all the reward!" He said, "No, not as long as you make supplication for them and praise them for it."