Sayyiduna Mughirah bin Shu’bah (may Allah be pleased with him) narrates: The Noble Prophet (peace and blessings be upon him) said:“When a person is in doubt and stands up (instead of sitting) after completing a rak‘ah, then if he has fully stood up, he should continue his prayer in that state and later perform two prostrations of forgetfulness (sajdah sahw). But if he has not fully stood up, he should sit down, and in this case, sajdah sahw will not be obligatory upon him.”