It has been narrated that the best hours of Fridays are these coming after the `Asr Prayer. Accordingly, it is recommended to repeat the following invocation one hundred times at that time:

اللَّهُمُّ صَلّ عَلَىٰ مُحَمَّدٍ وَآلِ مُحَمَّدٍ وَعَجِّلْ فَرَجَهُمْ

allahumma salli `ala muhammadin wa ali muhammadin wa `ajjil farajahum

O Allah, bless Muhammad and the Household of Muhammad and hasten their Relief.

Imam Ja`far al-Sadiq (peace be upon him) is reported as saying: i)To invoke Almighty Allah’s blessings upon the Prophet and his Household in the time between the Dhuhr and `Asr Prayers (on Fridays) is equal (in reward) to seventy rakats. ii)One who says the following invocation after the `Asr Prayer on Fridays will be awarded the reward of the righteous deeds of all men and jinn on that day: iii)One who repeats this invocation ten times immediately after the `Asr Prayer on Fridays will receive the blessings of the angels up to the next Friday and the very hour.

اَللَّهُمَّ صَلِّ عَلَىٰ مُحَمَّدٍ وَآلِ مُحَمَّدٍ

allahumma salli `ala muhammadin wa ali muhammadin

O Allah, bless Muhammad and the Household of Muhammad—

ٱلأَوْصِيَاءِ ٱلْمَرْضِيِّينَ

al-awsiya'i almardiyyina

the Successors and the pleased—

بِأَفْضَلِ صَلَوَاتِكَ

bi-afdali salawatika

with the best of Your blessings,

وَبَارِكْ عَلَيْهِمْ

wa barik `alayhim

and confer upon them

بِأَفْضَلِ بَرَكَاتِكَ

bi-afdali barakatika

with the best of your favors.

وَٱلسَّلاَمُ عَلَيْهِمْ

wa alssalamu `alayhim

And peace be upon them

وَعَلَىٰ أَرْوَاحِهِمْ وَأَجْسَادِهِمْ

wa `ala arwahihim wa ajsadihim

and upon their souls and bodies;

وَرَحْمَةُ ٱللَّهِ وَبَرَكَاتُهُ

wa rahmatu allahi wa barakatuhu

and Allah’s mercy and blessings be upon them.

Adding to this, Shaykh al-Tusi says that it is recommended to repeat the following invocation one hundred times at that time:

صَلَوَاتُ اللّهِ وَملاَئِكَتِهِ

salawatu allahi wa mala'ikatihi

The blessings of Allah, His angels,

وَأَنْبِيَائِهِ وَرُسُلِهِ

wa anbiya'ihi wa rusulihi

His prophets, His messengers,

وَجَميعِ خَلْقِهِ

wa jami`i khalqihi

and all of His creatures

عَلَىٰ مُحَمَّدٍ وَآلِ مُحَمَّدٍ

`ala muhammadin wa ali muhammadin

be upon Muhammad and the Household of Muhammad.

وَٱلسَّلاَمُ عَلَيْهِ وَعَلَيْهِمْ

walssalamu `alayhi wa `alayhim

And peace be upon him and upon them

وَعَلَىٰ أَرْوَاحِهِمْ وَأَجْسَادِهِمْ

wa `ala arwahihim wa ajsadihim

and upon their souls and bodies.

وَرَحْمَةُ ٱللَّهِ وَبَرَكَاتُهُ

wa rahmatu allahi wa barakatuhu

So be Allah’s mercy and blessings.

In al-Kafi, Shaykh al-Kulayni has narrated the following: When you complete the `Asr Prayer on Friday, say the following invocation.Almighty Allah will record for him one hundred thousand rewards, erase one hundred thousand of his evildoings, grant him one hundred thousand requests, and elevate him one hundred thousand ranks: He adds that if one repeats the same invocation seven times, Almighty Allah will give him rewards as many as His servants, accept his deeds on that day, and place light between his eyes on the Resurrection Day.

اَللَّهُمَّ صَلِّ عَلَىٰ مُحَمَّدٍ وَآلِ مُحَمَّدٍ

allahumma salli `ala muhammadin wa ali muhammadin

O Allah, bless Muhammad and the Household of Muhammad

ٱلأَوْصِيَاءِ ٱلْمَرْضِيِّينَ

al-awsya'i almardiyyina

the Successors and the pleased

بِأَفْضَلِ صَلَوَاتِكَ

bi-afdali salawatika

with the best of Your blessings,

وَبَارِكْ عَلَيْهِمْ

wa barik `alayhim

and confer upon them

بِأَفْضَلِ بَرَكَاتِكَ

bi-afdali barakatika

with the best of your favors.

وَٱلسَّلاَمُ عَلَيْهِ وَعَلَيْهِمْ

wa alssalamu `alayhi wa `alayhim

And peace be upon him and them

وَرَحْمَةُ ٱللَّهِ وَبَرَكَاتُهُ

wa rahmatu allahi wa barakatuhu

and Allah’s mercy and blessings be also upon them.

It is recommended to repeat seventy times after the `Asr Prayer so that sins will be forgiven:

أَسْتَغْفِرُ ٱللَّهَ وَأَتُوبُ إِلَيْهِ

astaghfiru allaha wa atubu ilayhi

I pray the forgiveness of Allah and I repent before Him.

Recite Dua Marefat-Allahumma Arrifni

Sayyid Ibn Tawus in his book of Jamal al-Usbu` mentions the dua of marefat of Imam Mahdi(ajtfs) after the `Asr Prayers on Fridays