What is the difference between "Subhanallah" (Glory be to Allah), "Subhanallahi wa bihamdihi" (Glory be to Allah and with His praise), and "Subhanallahi wa bihamdihi, Subhanallahil Azeem" (Glory be to Allah and with His praise, Glory be to Allah the Most Great) in terms of meaning and reward?

The difference between "Subhanallah" (Glory be to Allah) and "Subhanallahi wa bihamdihi" (Glory be to Allah and with His praise) is that the first means to declare Allah free from all imperfection, while the second adds praise to Allah Almighty. As for "Subhanallahi wa bihamdihi, Subhanallahil Azeem" (Glory be to Allah and with His praise, Glory be to Allah the Most Magnificent), it adds a repetition of glorification and describes Allah as the Most Magnificent, which indicates that there is no equal or peer to Him. Therefore, this last form of dhikr carries a greater reward due to its encompassing the declaration of Allah's freedom from imperfection, His praise, His magnification, and the repetition of glorification.