"The Messenger of Allah ﷺ ordered me to learn some statements from writings of the Jews for him, and he said: 'For indeed by Allah! I do no trust the Jews with my letters.'" He said: "Half a month did not pass before I learned it, when he ﷺ wanted to write to the Jews I would write it to them, and when they wrote to him I would read their letters to him."  

أَمَرَنِي رَسُولُ اللَّهِ ﷺ أَنْ أَتَعَلَّمَ لَهُ كَلِمَاتِ كِتَابِ يَهُودَ قَالَ إِنِّي وَاللَّهِ مَا آمَنُ يَهُودَ عَلَى كِتَابٍ قَالَ فَمَا مَرَّ بِي نِصْفُ شَهْرٍ حَتَّى تَعَلَّمْتُهُ لَهُ قَالَ فَلَمَّا تَعَلَّمْتُهُ كَانَ إِذَا كَتَبَ إِلَى يَهُودَ كَتَبْتُ إِلَيْهِمْ وَإِذَا كَتَبُوا إِلَيْهِ قَرَأْتُ لَهُ كِتَابَهُمْ