[Wyrd bið ful aræd]

Which leads to comparisons to the “No True Scotsman” bit. Everyone stumbles, so everyone’s faith stumbles. Thus nobody has assurance.

[MHGinTN]

You syllogized, “Everyone stumbles, so everyone’s faith stumbles. Thus nobody has assurance.” Logic is not you friend, eh? Absurd but sneaky false syllogism.

[metmom]

Stumbling does not rob someone of their assurance because our right standing before God depends on HIM, not our works.

[Elsie]

Everyone stumbles, so everyone’s faith stumbles.

You'll have to prove the logic here; as I do not see the conclusion is evident from the claim.