I am aware that research has been done on the topic of actions being multiplied by 70 times on Jumu’ah/Friday.
However I have found the narration in question in Mirqatul Mafatih and it would be extremely beneficial if Moulana could comment further on this narration.
Mulla ‘Ali Qari (rahimahullah) has mentioned this under the commentary of a Hadith. He has not cited a Hadith. He merely states: “Perhaps this is specific to Friday, since it has been reported that deeds are multiplied by seventy on Jumu’ah.” (لعل هذا مخصوص بيوم الجمعة إذ ورد: أن الأعمال في يوم الجمعة بسبعين ضعفا)
As mentioned in our answer here, Imam Razin (rahimahullah) has cited a narration of this meaning, but the chain first needs to be located before commenting.
(Jami’ul Usul, Hadith: 6867)
Imam Tabarani (rahimahullah) has recorded a narration which states that deeds are multiplied on Friday (without specifying a number). However, the chain consists of a liar.
(Al Mu’jamul Awsat, Hadith: 7891. Refer: Majma’uz Zawaid, vol. 2 pg. 164 and Lisanul Mizan, vol. 2 pg. 536, number: 2087)
It should be noted that Friday is called ‘Yawmul Mazid’, the day of extra. This could be used to prove that deeds are more rewarding on a Friday. See more here
And Allah Ta’ala Knows best.
Answered by: Moulana Suhail Motala
Approved by: Moulana Muhammad Abasoomar
This answer was collected from HadithAnswers.com. The answers were either answered or checked by Moulana Haroon Abasoomar (rahimahullah) who was a Shaykhul Hadith in South Africa, or by his son, Moulana Muhammad Abasoomer (hafizahullah), who is a Hadith specialist.