It is sufficient to understand the importance of this topic when Wahb ibn Munabbih رحمه الله (d. 110H) was asked "Is 'Laa ilaaha illallah' the key to Paradise?" He replied, "Yes indeed it is, but every key has teeth. So, if you bring the key with its teeth, Paradise will be opened for you; otherwise, it will not." Thus, we understand that the mere utterance of 'Laa ilaaha illallah' is not enough to enter Paradise and these conditions are the teeth to the key of Paradise.
Ongoing dars at Kochi. Alhamdullilah