Bayhaqi 4005 — What is reported on completing the obligatory prayers

(a) Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "The example of one who does not complete his prayer is like that of a pregnant female who, when the time to give birth draws near, miscarries, so that neither the pregnancy remains nor the child. And the example of the one who prays is also like that of a merchant: his profit is not secured for him until his capital is secured for him. Likewise, the voluntary prayers of the one who prays will not be accepted until he performs the obligatory ones."
(b) If this hadith is authentic, it is to be interpreted as referring to the voluntary acts that are within the obligatory prayer, whose validity is tied to the validity of the obligatory prayer; and the earlier hadiths are to be interpreted as referring to voluntary prayers outside the obligatory ones, whose validity does not depend on the validity of the obligatory prayers. And Allah knows best.