Is the conversion of a person valid if they stipulate that they will only perform two daily prayers instead of the required five?

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The conversion of a person who stipulates performing only two prayers is valid, but he will be held accountable for the five prescribed prayers. The meaning of Hakim ibn Hizam's pledge to the Prophet, peace be upon him, "I pledged to the Prophet that I would not bow except standing," is interpreted to mean he would not perform *ruku'* (bowing) during the prayer, but would proceed directly to *sujud* (prostration) after recitation.