Imam explains the matter in his famous book of "Forty Hadith" explains the matter as following:
Self-conditioning, contemplation and self-examination are essential pre-requisites for a seeker (mujahid) of truth who is battling with his self.
Self-conditioning or stipulation means binding oneself with the resolve not to do anything against God’s commands.
This is called musharatah, such as ‘I will not violate the Law of God today.’
It is very easy to stick to such condition for one day. Try to resolve, abide by your own resolve, and experiment, and you will see that how easy this task is.
Satan, the cursed creature, and his legions may magnify the volume of the task in your eyes, but these are the guiles played by the cheat.
Curse, and drive the Devil and evil thoughts from within the depths of the heart and the domain of your mind.
Experiment for one day and you will verify how easy this task is.