Reference: Siyar A’laam an-Nubalaa – Volume 3, Page 113
Fadhaalah ibn ‘Ubayd said:
For me to know that Allaah has accepted from me [a good deed equivalent to] the weight of a grain, is more beloved to me than this world and all that is in it. That is because He (Ta’aala) says:
{Indeed, Allaah only accepts from the righteous [who fear Him]}, soorah al-Maa.idah, aayah 27