We Muslims are commanded by Allah(SWT)to pray 5x a day. They are fixed at certain times. Our prayer(saalat)is very important.
Allah(SWT)says:
Be ever mindful of prayers, and of praying in the most excellent way; and stand before God in devout obedience. [Qur'an 2:238]
The Apostle of Allah was asked: Which of the actions is best? He replied: Observing prayer early in its period. [Abu Dawud 2: 426]
The first matter that the slave will be brought to account for on the Day of Judgement is prayer. If it is good, then the rest of his deeds will be good. And if it is bad, then the rest of his deeds will be bad. [At Tabarani]
The list goes on of the Quran and hadith reminding us of the importance of prayer.