These obligatory prayers must be performed in their due times by every Muslim who is pubescent, sane, and pure.
Without an excuse, it is unlawful to perform these prayers ahead of their times or to delay performing them until after their times have passed.It is an obligation to perform the prayers in their due times.
They must not be performed either before or after their due times, without a religious excuse.
To do this, one must know how each prayer time sets in and how it ends.
Allaah said in Soorat al-Maa^oon, Verses 4-5:
In these two verses, Allaah threatened with severe torture the ones who delay the prayers until after their times have passed.
Although some scholars judged the one who without a religious excuse intentionally delays performing his prayer until its time has passed as a blasphemer, the saying of the jumhoor (majority of scholars) is that this person is an enormous sinner and is very close to committing blasphemy, but not a blasphemer.
Being very close to the state of blasphemy means the person is committing one of the most enormous sins and he is under a great danger of committing blasphemy.
If a person performs the prayer before its time has set in without an excuse, his prayer is invalid.
Allaah said in Soorat an-Nisaa’, Verse #103:
It means: [Certainly, performing the prayers in their due times is an obligation on the believers.]
The one who delays the prayer (without an excuse) until after its time has passed is sinful.
However the prayer is valid and is considered a make up for the missed prayer.
The worse of the two cases, meaning the one that is more sinful, is the first case, i.e., to perform the prayer ahead of its time.
The person is more sinful in this case because his prayer is neither considered as fulfilling the obligation in due time nor as a make up prayer.
Moreover, the prayer is still due on him.
The one who combines the combinable prayers for a valid religious excuse, such as travelling, illness, or heavy rain is not sinful for doing so.
These cases contain well-known details that will be discussed later.