Question Summary:
If a person influences someone to sin will he get the sin also till the day of judgement?

Question Detail:

I have a question pertaining to sadkha jariuah.
 
If someone influences another Muslim to engage in any sin, and he continues doing that sin, and teachers others - will that person (who started it) get the sin written in his account indefinitely until the Day of Judgement even whilst he's in his grave? So, basically of sadkha jariah?

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
If one initiates a sin and if the sin continues, he will get the sin of the continuation of the sin. This is understood from the following Hadith,
فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ مَنْ سَنَّ فِي الإِسْلاَمِ سُنَّةً حَسَنَةً فَلَهُ أَجْرُهَا وَأَجْرُ مَنْ عَمِلَ بِهَا بَعْدَهُ مِنْ غَيْرِ أَنْ يَنْقُصَ مِنْ أُجُورِهِمْ شَىْءٌ وَمَنْ سَنَّ فِي الإِسْلاَمِ سُنَّةً سَيِّئَةً كَانَ عَلَيْهِ وِزْرُهَا وَوِزْرُ مَنْ عَمِلَ بِهَا مِنْ بَعْدِهِ مِنْ غَيْرِ أَنْ يَنْقُصَ مِنْ أَوْزَارِهِمْ شَىْءٌ ‏"‏ ‏.‏
The Messenger of Allah (ﷺ) said: He who sets a good precedent in Islam, there is a reward for him for this (act of goodness) and reward of that also who acted according to it subsequently, without any deduction from their rewards; and he who sets in Islam an evil precedent, there is upon him the burden of that, and the burden of him also who acted upon it subsequently, without any deduction from their burden. [Sahih Muslim 1017. Book 12, Hadith 88]
If a person initiated a wrong and he fears or knows that wrong is being perpetuated, he should openly retract from the wrong and also condemn the wrong. 
In such a situation it will not suffice that the person privately makes Tawbah. 
And Allah Ta’āla Knows Best
Bilal Ishaq (Issak)
Student Darul Iftaa
Leicester, England, UK
Checked and Approved by,
Mufti Ebrahim Desai.