I heard the Messenger of Allah ﷺ say: If any of you does not leave mukhabarah, he should take notice of war from Allah and His Apostle ﷺ. (Using translation from Abū Dāʾūd 3406)
سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ مَنْ لَمْ يَذَرِ الْمُخَابَرَةَ فَلْيُؤْذِنْ بِحَرْبٍ مِنَ اللهِ وَرَسُولِهِ