Read Ruku 77 of the Quran

إِنَّآ أَنزَلْنَآ إِلَيْكَ ٱلْكِتَـٰبَ بِٱلْحَقِّ لِتَحْكُمَ بَيْنَ ٱلنَّاسِ بِمَآ أَرَىٰكَ ٱللَّهُ ۚ وَلَا تَكُن لِّلْخَآئِنِينَ خَصِيمًۭا ﴿١٠٥﴾

Indeed, We have revealed to you, [O Muhammad], the Book in truth so you may judge between the people by that which Allah has shown you. And do not be for the deceitful an advocate.

وَٱسْتَغْفِرِ ٱللَّهَ ۖ إِنَّ ٱللَّهَ كَانَ غَفُورًۭا رَّحِيمًۭا ﴿١٠٦﴾

And seek forgiveness of Allah. Indeed, Allah is ever Forgiving and Merciful.

وَلَا تُجَـٰدِلْ عَنِ ٱلَّذِينَ يَخْتَانُونَ أَنفُسَهُمْ ۚ إِنَّ ٱللَّهَ لَا يُحِبُّ مَن كَانَ خَوَّانًا أَثِيمًۭا ﴿١٠٧﴾

And do not argue on behalf of those who deceive themselves. Indeed, Allah loves not one who is a habitually sinful deceiver.

يَسْتَخْفُونَ مِنَ ٱلنَّاسِ وَلَا يَسْتَخْفُونَ مِنَ ٱللَّهِ وَهُوَ مَعَهُمْ إِذْ يُبَيِّتُونَ مَا لَا يَرْضَىٰ مِنَ ٱلْقَوْلِ ۚ وَكَانَ ٱللَّهُ بِمَا يَعْمَلُونَ مُحِيطًا ﴿١٠٨﴾

They conceal [their evil intentions and deeds] from the people, but they cannot conceal [them] from Allah, and He is with them [in His knowledge] when they spend the night in such as He does not accept of speech. And ever is Allah, of what they do, encompassing.

هَـٰٓأَنتُمْ هَـٰٓؤُلَآءِ جَـٰدَلْتُمْ عَنْهُمْ فِى ٱلْحَيَوٰةِ ٱلدُّنْيَا فَمَن يُجَـٰدِلُ ٱللَّهَ عَنْهُمْ يَوْمَ ٱلْقِيَـٰمَةِ أَم مَّن يَكُونُ عَلَيْهِمْ وَكِيلًۭا ﴿١٠٩﴾

Here you are - those who argue on their behalf in [this] worldly life - but who will argue with Allah for them on the Day of Resurrection, or who will [then] be their representative?

وَمَن يَعْمَلْ سُوٓءًا أَوْ يَظْلِمْ نَفْسَهُۥ ثُمَّ يَسْتَغْفِرِ ٱللَّهَ يَجِدِ ٱللَّهَ غَفُورًۭا رَّحِيمًۭا ﴿١١٠﴾

And whoever does a wrong or wrongs himself but then seeks forgiveness of Allah will find Allah Forgiving and Merciful.

وَمَن يَكْسِبْ إِثْمًۭا فَإِنَّمَا يَكْسِبُهُۥ عَلَىٰ نَفْسِهِۦ ۚ وَكَانَ ٱللَّهُ عَلِيمًا حَكِيمًۭا ﴿١١١﴾

And whoever commits a sin only earns it against himself. And Allah is ever Knowing and Wise.

وَمَن يَكْسِبْ خَطِيٓـَٔةً أَوْ إِثْمًۭا ثُمَّ يَرْمِ بِهِۦ بَرِيٓـًۭٔا فَقَدِ ٱحْتَمَلَ بُهْتَـٰنًۭا وَإِثْمًۭا مُّبِينًۭا ﴿١١٢﴾

But whoever earns an offense or a sin and then blames it on an innocent [person] has taken upon himself a slander and manifest sin.