Accordingly, we say:

If any obligatory component of it is lacking, that perfection and completeness are lost. The designation may then be denied when what is intended is to deny that degree of perfection.

He must supply the missing component: if he omitted an obligation, he must perform it; or if he committed a sin, he must seek forgiveness for it. He thereby becomes one of those believers who deserve Allah’s pure reward, unmixed with punishment. If, however, he omits one of its obligations or commits a forbidden act, he deserves punishment for that and reward for what he has done. What is denied is the whole taken together, not every one of its parts. Similarly, if one is removed from ten, the ten are no longer ten, although most of their constituent parts remain.

The Sunnah likewise teaches regarding all other deeds, such as prayer and the like, that a person is rewarded for whatever part of them he performs (1) and punished for what remains unperformed. In fact, (2) if he has any voluntary worship, what he omitted is made up by it. If what he performed were invalid—its existence being equivalent to its absence—and earned him no reward, then nothing could be made up by supererogatory deeds. The hadith about the man who prayed incorrectly, recorded in the Sunan collections (3), indicates the same: when something in his prayer is deficient, he is rewarded for what he did perform.

If you were to say:

“The jurists state categorically that a person’s prayer, fasting, or Hajj is invalid if he omits one of its pillars.”

The response is:

That is because, in their terminology, “invalid” is the opposite of “valid,” whereas a valid act, in their terminology, is one that