All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
We have already issued Fataawa 83856, 88905, and 88389 clarifying the definition of Sunnah, and we have issued Fatwa 4049 clarifying that it is an obligation to follow the Sunnah of the Prophet .
However, the Sunnah that if someone abandons, he is not considered as misguided, is any desirable act for which its doer is rewarded and if someone does not do it, he is not punished, like optional charity, optional prayer, optional Hajj, optional fasting and other desirable acts of worship which are too many to mention.
As regards the Sunnah that if someone abandons he is considered as misguided, it is any obligatory act that is stated in the Sharee’ah, like ‘Eemaan (faith), the five pillars of Islam, being kind and dutiful to the parents, keeping ties with kinship and other obligations which will be too long to mention.
Finally, we advise you to seek religious knowledge so that you may distinguish between obligations and desirable acts and so that you would worship Allaah with insight.
Allaah Knows best.