The key to prayer is purification; its beginning is takbir and its end is taslim.  

قَالَ رَسُولُ اللَّهِ ﷺ مِفْتَاحُ الصَّلاَةِ الطُّهُورُ وَتَحْرِيمُهَا التَّكْبِيرُ وَتَحْلِيلُهَا التَّسْلِيمُ  

The Prophet ﷺ said: The key of prayer is purification; takbir (saying "Allah is most great") makes (all acts which break prayer) unlawful and taslim (uttering the salutation) makes (all such acts) lawful.  

قَالَ رَسُولُ اللَّهِ ﷺ مِفْتَاحُ الصَّلاَةِ الطُّهُورُ وَتَحْرِيمُهَا التَّكْبِيرُ وَتَحْلِيلُهَا التَّسْلِيمُ  

the Prophet ﷺ said: "The key to ṣalāh is purification, its taḥrīm (prohibition of all else during it) is through the takbīr (saying Allāhu akbar), and its taḥlīl (permissibily of all else after it) is the taslīm (saying the salām at the end)."  

عَنِ النَّبِيِّ ﷺ قَالَ: «مِفْتَاحُ الصَّلاَةِ الطُّهُورُ، وَتَحْرِيمُهَا التَّكْبِيرُ، وَتَحْلِيلُهَا التَّسْلِيمُ۔»  

Messenger of Allah said: "the key to Salat is the purification, its Tahrim is the Takbir, and its Tahlilis the Taslim, and there is no Salat for one who did not recite Al-Hamd and a Surah in the obligatory (prayer) or other prayers."  

قَالَ رَسُولُ اللَّهِ ﷺ مِفْتَاحُ الصَّلاَةِ الطُّهُورُ وَتَحْرِيمُهَا التَّكْبِيرُ وَتَحْلِيلُهَا التَّسْلِيمُ وَلاَ صَلاَةَ لِمَنْ لَمْ يَقْرَأْ بالْحَمْدُ وَسُورَةٍ _ فِي فَرِيضَةٍ أَوْ غَيْرِهَا  

"The Messenger of Allah said: 'The key to prayer is purification, its opening is to say 'Allahu Akbar' and its closing is to say As-salamu 'alaikum.'"  

قَالَ رَسُولُ اللَّهِ ﷺ مِفْتَاحُ الصَّلاَةِ الطُّهُورُ وَتَحْرِيمُهَا التَّكْبِيرُ وَتَحْلِيلُهَا التَّسْلِيمُ  

The Messenger of Allah ﷺ said: “The key to prayer is purification; entering it is takbeer and exiting it is tasleem.”  

قَالَ رَسُولُ اللهِ ﷺ مِفْتَاحُ الصَّلاةِ الطُّهُورُ وَتَحْرِيمُهَا التَّكْبِيرُ وَتَحْلِيلُهَا التَّسْلِيمُ  

The Messenger of Allah ﷺ said: “The key to prayer is wudoo’, entering it is takbeer and exiting it is tasleem.ʿ  

قَالَ رَسُولُ اللهِ ﷺ مِفْتَاحُ الصَّلاةِ الْوُضُوءُ وَتَحْرِيمُهَا التَّكْبِيرُ وَتَحْلِيلُهَا التَّسْلِيمُ  

The Messenger of Allah ﷺ said: “The key to prayer is purification; entering it is takbeer and exiting it is tasleem.” (Using translation from Aḥmad 1006)  

قَالَ رَسُولُ اللَّهِ ﷺ «مِفْتَاحُ الصَّلَاةِ الطُّهُورُ وَتَحْرِيمُهَا التَّكْبِيرُ وَتَحْلِيلُهَا التَّسْلِيمُ»  

The Messenger of Allah ﷺ said: “The key to prayer is wudoo’, entering it is takbeer and exiting it is tasleem.ʿ (Using translation from Aḥmad 1072)  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ «مِفْتَاحُ الصَّلَاةِ الْوُضُوءُ وَتَحْرِيمُهَا التَّكْبِيرُ وَتَحْلِيلُهَا التَّسْلِيمُ»  

The Messenger of Allah ﷺ said: “The key to prayer is purification; entering it is takbeer and exiting it is tasleem.” (Using translation from Aḥmad 1006)  

عَنْ رَسُولِ اللهِ ﷺ قَالَ «مِفْتَاحُ الصَّلَاةِ الطُّهُورُ وَتَحْرِيمُهَا التَّكْبِيرُ وَتَحْلِيلُهَا التَّسْلِيمُ»  

The Messenger of Allah ﷺ said: “The key to prayer is purification; entering it is takbeer and exiting it is tasleem.” (Using translation from Aḥmad 1006)   

قَالَ رَسُولُ اللهِ ﷺ مِفْتَاحُ الصَّلَاةِ الطُّهُورُ وَإِحْرَامُهَا التَّكْبِيرُ وَإِحْلَالُهَا التَّسْلِيمُ  

The Messenger of Allah ﷺ said: “The key to prayer is purification; entering it is takbeer and exiting it is tasleem.” (Using translation from Aḥmad 1006)   

مِفْتَاحُ الصَّلَاةِ الطَّهُورُ وَإِحْرَامُهَا التَّكْبِيرُ وَانْقِضَاؤُهَا التَّسْلِيمُ  

The Messenger of Allah said: "The key to prayer is purification, its opening is to say Allahu Akbar and its closing is to say As-salamu 'alaikum." (Using translation from Ibn Mājah 276)   

عَنْ عَلِيٍّ ؓ رَفَعَهُ إِلَى النَّبِيِّ ﷺ قَالَ مِفْتَاحُ الصَّلَاةِ الطُّهُورُ وَإِحْرَامُهَا التَّكْبِيرُ وَإِحْلَالُهَا التَّسْلِيمُ  

"مِفْتَاحُ الصَّلاةِ الطُّهُورُ، وَتَحْرِيمُهَا التَّكْبِيرُ، وَتَحْلِيلُهَا التَّسْلِيمُ".

. . . .  

"عَنِ ابْنِ مَسْعُودٍ قَالَ: مِفْتَاحُ الصَّلاةِ التَّكْبِيرُ، وَانْقِضَاؤُهَا التَّسْلِيمُ، وَفِى لَفْظٍ: وَتحْلِيلُهَا التَّسْلِيمُ".