Allah Ta'ala has granted many distinctions to Monday. The Holy Prophet (Sallallahu alaihi wa sallam) was born on Monday, He (Sallallahu alaihi wa sallam) declared His Prophethood on Monday, the command for Hijra also came on Monday, the demise of the Holy Prophet (Sallallahu alaihi wa sallam), which is a special day for the Ummah also was on Monday. The night in which the journey of Meraj occurred is also Monday.
Thus, Monday also has been granted excellence and has been made almost an equal to Friday, so that another witness is also ready for the Ummah. In this way, all arrangements have been made for the Maghfirah (forgiveness) of the Ummah.
Two days and 2 nights in the week make the dark deeds of the Ummah more radiant, so that in Qiyamah, the Ummah is presented more radiant than all others. Because of the blessings of these days, even the minutest good deeds of the Ummah will turn into huge mountains of virtue. This was the reason why Monday was made the night of Meraj.