Messenger of Allah (S) said: "As-Salat is two and two, with a Tashahhud for every two Rakʿah, with humility, imploring, having a sense of tranquility, pleading and showing helplessness and stretching out your hand" - he said: raising them - "to your Lord, with the insides of them facing your face, saying: 'O Lord! O Lord! And whoever does not do this, then it is like this or that." (Using translation from Tirmidhī 385)   

قَالَ رَسُولُ اللهِ ﷺ «الصَّلَاةُ مَثْنَى مَثْنَى تَشَهَّدُ فِي كُلِّ رَكْعَتَيْنِ وَتَضَرَّعُ وَتَخَشَّعُ وَتَمَسْكَنُ وَتُقْنِعُ يَدَيْكَ» يَقُولُ تَرْفَعُهُمَا إِلَى رَبِّكَ مُسْتَقْبِلًا بِبُطُونِهِمَا وَجْهِكَ وَتَقُولُ يَا رَبِّ يَا رَبِّ فَمَنْ لَمْ يَفْعَلْ ذَلِكَ كَذَا وَكَذَا يَعْنِي خِدَاجٌ خَالَفَهُ شُعْبَةُ  

“The Messenger of Allah ﷺ said: ‘The night prayers are (to be offered) two by two. Say the Tashah-hud after each two Rakʿah, and raise your hands in all humility like one who is poor and needy and say: ‘Allāhummaghfir lī (O Allah, forgive me).’ And whoever does not do that, it is imperfect.’” (Using translation from Ibn Mājah 1325)   

عَنْ رَسُولِ اللهِ ﷺ قَالَ الصَّلَاةُ مَثْنَى مَثْنَى وَتَشَهَّدُ فِي كُلِّ رَكْعَتَيْنِ وَتَبَاءَسُ وَتَمَسْكَنُ وَتُقْنِعُ يَدَيْكَ وَتَقُولُ اللهُمَّ اللهُمَّ فَمَنْ لَمْ يَفْعَلْ ذَلِكَ فَهِيَ خِدَاجٌ