What is the ruling on delaying prayer without a reason?

Delaying prayer beyond its prescribed time until it becomes a make-up (qada') is among the severe prohibitions. Scholars have interpreted the squandering of prayer in Allah's Almighty saying: (Then, there succeeded them a progeny who neglected prayers and pursued lusts; so, they will meet Ghayy (i.e. Hell)) as delaying it beyond its due times. Allah Almighty has indeed ordained the performance of prayer within its time: (Indeed, prayer has been decreed upon the believers a book [to be observed at] fixed times).

As for delaying it from the very beginning of its time, there is no harm in that, though one misses the virtue of praying at the earliest time. However, if there is no excuse for abandoning the congregation (jama'ah), then congregational prayer is obligatory, based on the Prophet's (peace be upon him) saying: "Whoever hears the call (to prayer) and does not come to it, there is no prayer for him except for one with an excuse."