Leads One To Infidelity
The real dependence is on the end. If one's end comes with correct beliefs, there is hope of success from Allah; otherwise there is nothing but loss.
Hence, one should fear the smallest or the biggest thing whereby faith and belief are adversely affected, more than ones fear of fire etc., so that no such sentence regarding the Shari'ah or divine commandments or the Sunnahs should escape the tongue whereby one maybe deprived of faith; because this thing grows up insidiously and slowly.
First of all man considers a praiseworthy act lightly, then he moves onto something above it, and then another, until the holding in disdain of one praiseworthy act at last leads man to infidelity, as Hazrat Shah Abd al-Aziz Muhaddith Dehlavi writes: -
"When man considers the civil mores and praiseworthy acts of the Shari'ah trivial, he is punished with the deprivation of the sunnah, and he who considers the sunnah lightly, he is given the torture of deprivation of obligatory duties and he who takes obligatory duties lightly is involved in deprivation of gnosis. That is, once starting, this chain of events does not stop but goes on until a wealth like that of faith goes out of his heart.”