The first matter that the servant will be held accountable for on the Day of Judgment is the prayer. If it is sound, then the rest of his deeds will be sound. And if it is corrupt, then the rest of his deeds will be corrupt.

Abu Hurairah - Sunan al-Tirmidhi

Pray as you have seen me praying.

Malik ibn al-Huwayrith - Sahih Bukhari

Whoever prays Isha in congregation, it is as if he prayed half the night. And whoever prays Fajr in congregation, it is as if he prayed the whole night.

Uthman ibn Affan - Sahih Muslim