Prayer is Obligatory for Every Muslim:

The Salah is the most important pillar of Islam after proclamation of the faith (the Sahada). Performing salah is obligatory for Every Muslim. 

ذَٰلِكَ الْكِتَابُ لَا رَيْبَ ۛ فِيهِ ۛ هُدًى لِلْمُتَّقِينَ

الَّذِينَ يُؤْمِنُونَ بِالْغَيْبِ وَيُقِيمُونَ الصَّلَاةَ وَمِمَّا رَزَقْنَاهُمْ يُنْفِقُونَ

“This is the Book in which there is no doubt, a guidance for those who have Taqwa: who believe in the unseen, and who establish Salah, and spend out of what we have provided for them.” (2:2-3) [ Al-Quran ]

وَمَا أُمِرُوا إِلَّا لِيَعْبُدُوا اللَّهَ مُخْلِصِينَ لَهُ الدِّينَ حُنَفَاءَ وَيُقِيمُوا الصَّلَاةَ وَيُؤْتُوا الزَّكَاةَ ۚ وَذَٰلِكَ دِينُ الْقَيِّمَةِ

And they have been commanded no more than this: To worship Allah, offering Him sincere devotion, being true (in faith); to establish regular prayer; and to practise regular charity; and that is the Religion Right and Straight. [ Al-Quran ]

إِنَّنِي أَنَا اللَّهُ لَا إِلَٰهَ إِلَّا أَنَا فَاعْبُدْنِي وَأَقِمِ الصَّلَاةَ لِذِكْرِي

"Verily, I am Allah: There is no god but I: So serve thou Me (only), and establish regular prayer for celebrating My praise. [ Al-Quran ]

 وَأَقِيمُوا الصَّلَاةَ وَآتُوا الزَّكَاةَ وَأَطِيعُوا الرَّسُولَ لَعَلَّكُمْ تُرْحَمُونَ

So establish regular Prayer and give regular Charity; and obey the Messenger; that ye may receive mercy. [ Al-Quran ]

مَا كَانَ مُحَمَّدٌ أَبَا أَحَدٍ مِنْ رِجَالِكُمْ وَلَٰكِنْ رَسُولَ اللَّهِ وَخَاتَمَ النَّبِيِّينَ ۗ وَكَانَ اللَّهُ بِكُلِّ شَيْءٍ عَلِيمًا

++++ Muhammad is not the father of any of your men, but (he is) the Messenger of Allah, and the Seal of the Prophets: and Allah has full knowledge of all things. [ Al-Quran ]

الَّذِينَ يُقِيمُونَ الصَّلَاةَ وَيُؤْتُونَ الزَّكَاةَ وَهُمْ بِالْآخِرَةِ هُمْ يُوقِنُونَ

Those who establish regular Prayer, and give regular Charity, and have (in their hearts) the assurance of the Hereafter. [ Al-Quran ]

وَالَّذِينَ يُمَسِّكُونَ بِالْكِتَابِ وَأَقَامُوا الصَّلَاةَ إِنَّا لَا نُضِيعُ أَجْرَ الْمُصْلِحِينَ

As to those who hold fast by the Book and establish regular prayer,- never shall We suffer the reward of the righteous to perish. [ Al-Quran ]

وَإِذَا نَادَيْتُمْ إِلَى الصَّلَاةِ اتَّخَذُوهَا هُزُوًا وَلَعِبًا ۚ ذَٰلِكَ بِأَنَّهُمْ قَوْمٌ لَا يَعْقِلُونَ

When ye proclaim your call to prayer they take it (but) as mockery and sport; that is because they are a people without understanding. [ Al-Quran ]

لَٰكِنِ الرَّاسِخُونَ فِي الْعِلْمِ مِنْهُمْ وَالْمُؤْمِنُونَ يُؤْمِنُونَ بِمَا أُنْزِلَ إِلَيْكَ وَمَا أُنْزِلَ مِنْ قَبْلِكَ ۚ وَالْمُقِيمِينَ الصَّلَاةَ ۚ وَالْمُؤْتُونَ الزَّكَاةَ وَالْمُؤْمِنُونَ بِاللَّهِ وَالْيَوْمِ الْآخِرِ أُولَٰئِكَ سَنُؤْتِيهِمْ أَجْرًا عَظِيمًا

But those among them who are well-grounded in knowledge, and the believers, believe in what hath been revealed to thee and what was revealed before thee: And (especially) those who establish regular prayer and practise regular charity and believe in Allah and in the Last Day: To them shall We soon give a great reward.[ Al-Quran ]