Is vowing to say "I seek refuge in Allah from associating with Him what we know and what we do not know" five times, along with saying "There is no god but Allah" five times upon feeling ostentation, considered an innovation? And what must be done after stopping this dhikr?

Hypocrisy (Riyaa’) is a type of shirk (associating partners with Allah). One way to cure it is to recite the authentic supplication (du’a) for protection from it. However, saying “La ilaha illa Allah (There is no god but Allah)” five times when fearing hypocrisy has not been authentically reported (as a prescribed act), and therefore it is an innovation (bid’ah). The fundamental principle in worship is strict adherence to what is prescribed (Tawqeef).

Therefore, one must fulfill a permissible vow, which is to make the supplication when feeling hypocrisy. It is not permissible to fulfill an impermissible vow (reciting “La ilaha illa Allah” five times).

If the wording of the vow implies repetition, such as “Every time or whenever hypocrisy enters my heart, I will say the supplication,” then the expiation is repeated each time this supplication is not recited. The expiation intended here is the expiation for breaking an oath.