The importance of prayer
The Messenger of Allah (sal Allahu alaihi wa sallam) said, “The first deed for which people will be brought to account on the Day of Resurrection will be their prayer. Our Lord will say to His angels, ‘Look at the prayer of My slave whether it is complete.’ If it is complete, it will be recorded as being complete, but if anything is lacking, He will say, ‘Look and see whether My slave offered any voluntary prayers.’ If he did any voluntary prayers, He will say, ‘Complete My slave’s obligatory prayers from his voluntary prayers.’ Then all other deeds will be judged in the like manner.”
[Abu Dawud - Classed as Sahih by Sh al-Albaani]
The above Hadith informs us of the first duties towards Allah for which a person will be brought to account, and this will be the Salaah (prayer).
In another narration (which is Sahih & found in Sunan at-Tirmidhi & Sunan an-Nasaa’i) the Prophet (sal Allahu alaihi wa sallam) said, “If it (the prayer) is good he (the person being judged) will succeed and prosper, and if it is bad then he will be a loser and doomed.”
The above Hadith informs us of the priority of the obligatory actions above the voluntary. So a person should first and foremost strive to implement and perfect what Allah has made obligatory upon him.
The above Hadith also informs us of the importance and priority of the five obligatory daily prayers which a person should strive to perfect by performing them according to the way of the Prophet (sal Allahu alaihi wa sallam) and by also praying them on time.
Lastly, the above Hadith also informs us of the importance of the voluntary actions which not only serve as a barrier and protection from leaving the obligatory but also they are a sort of backup for those who have shortcomings in fulfilling the obligatory actions.
And Allah knows best!