How to repay someone’s favours..

قال الرسول صلى الله عليه و سلم

وَمَنْ صَنَعَ إِليكم معروفا فكافئوه فإن لم تجدوا ما تكافئوه فادْعُوا له حتى تَرَوْا أنكم قد كافأتموه

أبو دَاوُدَ

قال صاحب الكتاب عون المعبود في شرح الحديث:

أنكم قد كافأتموه ) : أي كرروا الدعاء حتى تظنوا أن قد أديتم حقه . وقد جاء من حديث أسامة مرفوعا : من صنع إليه معروف فقال لفاعله جزاك الله خيرا فقد أبلغ في الثناء رواه رواه النسائيوالترمذيوابنحبان

،فدل هذا الحديث على أن من قال لأحد : جزاك الله خيرا مرة واحدة ، فقد أدى العوض وإن كان حقه كثيرا

The Prophet (peace & blessings be upon him) said:

“If anyone does something good for you, then repay him. If you do not have the means to repay him, then supplicate for him, until you feel that you have repaid him.”

Abu Dawud 1672

In explaining the Hadith the shaykh said:

“until you feel that you have repaid him”

Meaning: keep on praying for the person until you think you have repaid him for his rights.

In another Hadith collected in Tirimidhi the prophet صلى الله عليه و سلم is reported to have said:

“Whoever has a favour done for him and says to the one who did it, ‘JazakAllah khair,’ has done enough to thank him.”

So this hadith proves whoever says جزاك الله خيراً once to someone, has repaid their favour even if it was a large amount.