Innovations are rejected

Arabic

مَنْ أَحْدَثَ فِي أَمْرِنَا هَذَا مَا لَيْسَ مِنْهُ فَهُوَ رَدٌّ.

Commentary

The charter against bidʿah. The religion was completed during the Prophet's ﷺ life; what he did not do in worship, no one after him gets to add. Note the scope: 'this affair of ours' means the religion, not everyday life.