Questioned posed to al-Allaamah Shaykh Saalih al-Fawzaan (may Allaah preserve him)
Q. What is the ruling of the one who fast the blessed (month of) Ramadaan without praying at all with no (legislated) excuse, knowing that we have advised him many times, but he has not listened?
A. The one who waste the prayer, the fast nor any other action is considered sound (i.e. accepted) from him. That is because the one who abandons the prayer has disbelieved and the action that comes from the disbeliever is not sound (i.e. accepted). The prayer is the second pillar from the pillars of Islaam and the fast is the fourth pillar. Therefore the prayer is given precedence over the fast and it is the pillar of Islaam.
Therefore the one who doesn’t pray, his fast or any other action is not accepted from him. Upon him is to repent to Allaah The Glorified and Most High and preserve the five daily prayers. Then after that, he preserves the rest of the affairs of his religion from the fast and other than it.
As long as he is not praying he is not a Muslim and his actions are not accepted from him. The prayer is the pillar of Islaam. Does a building stand without a pillar!? This is impossible.”