Is strong Iman a prerequisite to fulfilling obligations?

Every Hukm has a prerequisite, but the texts identify those prerequisites, not us.

So, the Aya of Wudu says that before we stand up for salat, then we must do Wudu or Ghusl. It identified the prerequisite. And the Ahadith that speak about marriage required that we first attain the approval of the Wali, pay the Mahr and so on, so those are defined as prerequisites.

But when you look at the texts of the Qur'an and Sunna, you will find an interesting thing. Nowhere is "strengthening your iman" set as a prerequisite for any obligation, rather it is defined as an objective independent of all other objectives. Not only that, it is defined as an objective that we have only partial control over, where the Hadith says "Hearts are between two (fingers) from the (fingers) of Allah, He flips it however He wills." iman is a constant struggle; it goes up and down however Allah (swt) wills and it is our responsibility to constantly maintain it. But nowhere in Islam does it say that strong iman is a prerequisite for any of the obligations.

The Qur'an even says "it may be that you hate something and it is good for you." How can anyone with strong iman hate a command of Allah (swt)? It is an Aya that clearly teaches us that you must do your obligations even if your iman is weak, even if your motivation is weak, even if you don't want to do it. You still get up and do it.

So, no one is saying we focus on the khilafah and neglect our iman. Rather we are saying that they are both independent obligations and must be worked on simultaneously.

To only focus on iman and think that you can ever reach perfection is to chase a mirage. iman will naturally strengthen and weaken and we are always working on it, independent of all other obligations.