Tafsir of Al-Ma'aarij 70:34

And those who are with their Salah, Yuhafizun. meaning, they maintain its proper times, its pillars, its obligations and its recommended acts. So Allah begins this discussion (of the believers' attributes) with prayer and He concludes it with prayer. This proves the importance of it and the praise of its noble status, just as what preceded at the beginning of Surah Al-Mu'minun. It is exactly the same discussion. This is why Allah says there (in Al-Mu'minun),

أوليك هم الورثون

الذين يرثون الفردوس هم فيها خلدون

These are indeed the inheritors. Who shall inherit the Firdaws (Paradise). They shall dwell therein forever. (23:10-11) And He says here,

أوليك في جنات مكرمون