In the Name of God
Holy Prophet(S.A.) :
The month of Rajab is linked to Almighty Allah as Sha'ban to the Holy Prophet (S.A.) and Ramadhan to his Ummah and fighting theinfield in it is Haram. Whoever observes fast (even one day) during the month of Rajab gets Allah’s pleasure and Allah’s indignation and anger will distant from him and one gate of the gates of the Hell will be shut on him.
Imam Musa ibne Ja’far (A.S.):
Whoever keeps fast one day in the month of Rajab the fire of Hell distant from him for a year and whoever keeps fast for three days for sure he will be in paradise and he has also said that Rajab is the name of a river in the paradise which is whiter than milk and sweeter than honey and whoever keeps fast for one day for sure he will drink from that river.
Imam Sadiq (A.S.):
The Holy Prophet said that the month of Rajab is the month of seeking and asking forgiveness for his Ummah. Then, ask Allah to forgive you as Allah is all-forgiving and all-merciful and Rajab is called "Assab" It means pouring out, full of love and kindness, as Allah’s blessing is poured on my Ummah in abundance. Therefore, say a lot:
"Astaghferollah wa as’ allohottoubah".
"I ask Allah for forgiveness and ask Him to accept my repentance."