Harb ibn Ubaydullah told on the authority of his grandfather, his mother's father, that he had it on the authority of his father that the Messenger of Allah ﷺ said: Tithes are to be levied on Jews and Christians, but not on Muslims. (Using translation from Abū Dāʾūd 3046)   

أَنَّهُ سَمِعَ رَسُولَ اللهِ ﷺ يَقُولُ لَيْسَ عَلَى الْمُسْلِمِينَ عُشُورٌ إِنَّمَا الْعُشُورُ عَلَى الْيَهُودِ وَالنَّصَارَى