Is it permissible to set a specific number for daily remembrance (dhikr), such as 1,000 acts of seeking forgiveness (istighfar), at any time of the day? And if this is an innovation (bid‘ah), what is the view on Ibn Taymiyyah’s act of seeking forgiveness 1,000 times when a matter became difficult for him?

The statement that performing a specific, non-narrated number of dhikr (remembrance of Allah) is an 'additive bid‘ah' (innovation) applies when that number is adhered to and considered part of the Sunnah. However, if it occurs without such adherence or without being taken as a Sunnah, then there is no harm in it, due to the general command to remember Allah, and this includes seeking forgiveness (istighfar). No one says that it is impermissible to seek forgiveness a thousand times or more; rather, for one who consistently seeks forgiveness, Allah will grant him relief and a way out. However, considering a non-narrated number as Sunnah is what is meant by 'additive bid‘ah.'