What is reckoning (ihtisab) in Sharia, how is it done, and how can I be certain that I have reckoned it for Allah?

Ihtisab (seeking reward from God) is patience, seeking the pleasure of Allah, complying with His command, being content with His decree, and seeking reward from Him, the Almighty. It involves patience at the first shock, acceptance of Allah's decree, refraining from discontent and despair, and reciting Istirja' (إِنَّا لِلّهِ وَإِنَّا إِلَيْهِ رَاجِعونَ - "Indeed we belong to Allah, and indeed to Him we will return") upon affliction, as Allah the Almighty says: {And give good tidings to the patient, who, when disaster strikes them, say, "Indeed we belong to Allah, and indeed to Him we will return." Those are the ones upon whom are blessings from their Lord and mercy. And it is those who are the [rightly] guided.} A servant who practices ihtisab is known by these qualities. Deeds are judged by intentions, so if one's patience is purely for Allah's sake, then they will receive the reward mentioned in the Hadith (definition); otherwise, they will not.