Shaykh Abdul Azeez ibn Baz rahimahullaah was asked:
Q: What is meant by “The types of worship are ‘tawqeefeeyah’?” (Restricted to textual evidence)
A: It means that they aren’t established except by way of legislation – they are not established by the opinions of the people.
A saying or action is not counted as being from the acts of worship except with a textual proof from Allaah or from the Messenger of Allaah; from the Quraan or the Prophetic Sunnah.
As for the people saying “This is an act of worship” then no, (rather worship is) tawqeefeeyah; meaning: there must be a textual evidence regarding such – from Allaah – as He is the Legislator.
Just as the Prophet sallAllaahu `alaihi wa sallam said in the authentic narration: “Whoever invents into this affair of ours that which is not from it, then it is rejected.” Meaning: it is refused.
And he sallAllaahu `alaihi wa sallam said: “Whoever performs an action that is not in accordance with our affair, then it is rejected.” Meaning: it is refused.
And he used to say in his sermons – sallAllaahu alaihi wa sallam – on Friday and at other times: “Then to proceed: Indeed the best of speech is the Speech of Allaah, and the best of guidance is the guidance of Muhammad – sallAllaahu alaihi wa sallam – and the worst of affairs are the newly invented matters, and every newly invented matter is misguidance.”
So it is not for anyone to come with new legislation; rather we must restrict ourselves to the Legislation of Allaah.
So if a person were to say: “It is prescribed for the people to pray a sixth prayer during the daytime, at ten o clock in the morning – before Dhur” –; or “There is a sixth prayer in the middle of the night, other than Ishaa” – then this is not legislated.
Rather this is something false and a newly invented matter (bid`ah); it is not allowed.
Or if a person were to say; “The people must fast another month – other than Ramadaan” or “It is prescribed for them to fast a month that Allaah did not prescribe” then this is something newly invented (a bid`ah).
Or if someone were to say: “It is prescribed for the people to pray a specific prayer, three units (rak`ahs) – other than the Witr prayer; during the daytime three units (rak`ahs), or five units (rak`ahs) – with such and such an intention, or with such and such an intention”, intending by way of that worship: this is false and futile.
Worship is in twos, or four, or eight – the intent is an even number.
So the Prophetic Sunnah is in twos during the day, and what is obligatory during the night is in twos except for that which Allaah has legislated from the Witr prayer, which is three, or five – as has come in the narration (hadeeth).
What is meant is: it is not for anyone to prescribe something new.
It is not for anyone to prescribe something that has not been legislated in the Book or the Prophetic Sunnah; whether that be from saying or action.
[Source: http://www.binbaz.org.sa/mat/10494 ]