Intending four rak‘as in a non-emphasized sunna

Question

[A person] made the niyya of four [rak‘as] in a non-emphasized sunna, but because the congregation of asr stood up, he ended [the prayer] with the salam after two rak‘as. As for those four that he had made wajib upon himself: when is it necessary to complete them — or is it a sunna — or did they lapse by praying two?

Answer

Merely by beginning with the niyya of four [rak‘as], four did not become wajib; only two became wajib. When he gave the salam after two, the wajib was fulfilled; it is not obligatory to pray two more for it.

Source: Fatawa Mahmudiyya

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