There is no doubt that Allaah Ta’aalaa created all the days and nights and that they are all His.  But we have to understand, which days are the
ones we are specifically commanded to remember? The respected chief of interpreters
of Qur’aan Hazrat Ibne Abbaas, Hazrat Ubaiy Ibne Ka’ab, Hazrat Mujaahid and
Hazrat Qataadah (Allaah be pleased with them) along with several other interpreters say, “the days of Allaah refer
to those days on which Allaah  bestowed rewards
to His bondsmen”.  (Ibne Jareer, Khaazin, Madaarik, Mufridaat,  Raaqhib)

The true believers know that Almighty Allaah’s greatest blessing is the King of Both Worlds, the Reason of all Creation, The Mercy Unto the
Worlds, the Intercessor of the Sinful, Hazrat Ahmad-e- Mujtabaah Muhammad Mustafaa (Sallal Laahu ‘Alaiehi Wa
Sallam). All other blessings are because of him, if
he was not created than nothing else would have been created. So to revive the memories of the day that the greatest blessing was bestowed and to tell others  that this is the day
Allaah bestowed great blessing on all Muslims by sending His beloved Prophet (Sallal Laahu ‘Alaiehi Wa Sallam)is
definitely obeying the command of Allaah. And to follow any command of Allaah
is not an innovation but is a cause of blessing and mercy.  Based on this, consideration must be given to
those days on which great events took place and Divine blessings were bestowed
on respected holy people of Islaam.