Alms of any day are very important. However, specifically on Friday, Allah rewarded him "more". The reason is, Friday is the main day in Islam - the Muslim weekly holiday.
"Indeed, on Friday there is a mustajab time. If a Muslim servant performs prayers and prays to Allah, undoubtedly it will be granted ... " (Muttafaqun 'Alaih).
"In fact, the alms on Friday have advantages over other days. The alms on that day are compared to other days of the week, like alms during the month of Ramadan when compared to all other months. " (Ibnul Qayyim, Zadul Ma'ad).
"And the alms on that day (Friday) are more glorious than any other day". (Narrated by Ibn Khuzaimah, Mauquf Sahih). Allah knows best. (mel / localhost / project / personal / ddhongkong.org / ddhongkong.org). *
