sentence1: So then, brothers, stand firm and hold the traditions which you were taught by us, whether by word or by letter.
sentence2: فَاثْبُتُوا إِذَنْ، أَيُّهَا الإِخْوَةُ، وَتَمَسَّكُوا بِالتَّعَالِيمِ الَّتِي تَلَقَّيْتُمُوهَا مِنَّا، سَوَاءٌ كَانَ بِالْكَلاَمِ أَمْ بِرِسَالَتِنَا.