The Quran

فَلِذٰلِكَ فَادعُ ۖ وَاستَقِم كَما أُمِرتَ ۖ وَلا تَتَّبِع أَهواءَهُم ۖ وَقُل آمَنتُ بِما أَنزَلَ اللَّهُ مِن كِتابٍ ۖ وَأُمِرتُ لِأَعدِلَ بَينَكُمُ ۖ اللَّهُ رَبُّنا وَرَبُّكُم ۖ لَنا أَعمالُنا وَلَكُم أَعمالُكُم ۖ لا حُجَّةَ بَينَنا وَبَينَكُمُ ۖ اللَّهُ يَجمَعُ بَينَنا ۖ وَإِلَيهِ المَصيرُ

(Saheeh International)

So to that [religion of Allāh] invite, [O Muḥammad],¹ and remain on a right course as you are commanded and do not follow their inclinations but say, "I have believed in what Allāh has revealed of scripture [i.e., the Qur’ān], and I have been commanded to do justice among you. Allāh is our Lord and your Lord. For us are our deeds, and for you your deeds.² There is no [need for] argument between us and you.³ Allāh will bring us together, and to Him is the [final] destination."

Another meaning understood from the Arabic is "So because of that [division and separation into sects], invite [them back to Allāh]…"
i.e., the consequences thereof.
Since the truth has been made clear and since those who refuse it do so only out of stubbornness or worldly interests.