Two of them were definitely earlier than Tabari, so even if Tabari were found to be uncritical, that would not significantly affect anything as we still have the other three. A Muslim might wish all the early biographers of Mohammed were so severely flawed, but multiple sources indicate their accuracy.
Wawili kati yao waliandika kabla ya Tabari, kwa hiyo hata kama Tabari alionekana kutokuwa mhakiki, jambo hilo haliwezi kuathiri kitu chochote kwa kiasi kukubwa kwani bado tuna watu wengine watatu. Muislam anaweza kupenda kuona kuwa waandishi wote wa maisha ya Muhammad wanaonekana kuwa na dosari sana, lakini vyanzo mbalimbali vinaonyesha usahihi wao.