Marziyeh Hadidechi On Prayer Allah (SWT) says in the Holy Qur'an...
(2:238) The Holy Prophet (s) is reported to have said: افضل الاعمال عند الله الصلاة في اول وقتها “The best of deeds to Allah is prayer in the beginning of its time” What follows are thought provoking memoirs of people who got the advantage to observe great Muslim scholars at prayer time: A) A youth extremely observant of prayer time "Of the important distinguishing characteristics of Imam Khumayni was that he always performed the prayer at the beginning of its time, and would give importance to the recommended prayers ( nawafil ) .
This characteristic was present in him since the beginning of his youth age, when he hadn't exceeded twenty years. Some friends used to say: "We thought in the beginning that God forbid, he performs his prayers at the beginning of its time, out of show off. For this very reason, we tried to do something that if this action was out of showiness, we stop the same. For a long time we thought of it, and tried him several times in various ways.
For example, exactly at the beginning of the prayer time, we would spread the table cloth (for having our meals); or arrange to set out on a journey. However, he would say, 'You go on with your food, and I shall perform my prayers. I shall eat whatever remains.' Or while leaving for a journey (at the beginning of the prayer time) he would say: 'You go ahead.
I shall follow and reach you.' A long time had passed since this matter took place, and not only was his timely prayer not left, he (also) compelled us to perform our prayers at the beginning of its time." Muhammad `Abai B) What imam al-Sadiq (`a) actually meant "The other issue was prayer at the beginning of its time, that he lay great importance to.
He would narrate a tradition from Imam Ja’far al-Sadiq that said: 'If a person takes his prayer lightly, he shall be deprived of our intercession.' Once I said to him: 'Taking prayers lightly may mean that a person sometimes performs his prayers, while sometimes he does not.' He said: 'No. This, rather, is against the religion.