Is it necessary to renew the marriage contract for someone who denied the obligation of prayer for a few hours after the contract and before consummation, and then repented and retracted his denial?

First: Whoever denies the obligation of prayer, while being aware of it, is judged to have disbelieved and apostatized from Islam, unless they are ignorant, such as a recent convert to Islam or someone raised in a remote area. This is by agreement of the Imams.

Second: If someone apostatizes after the marriage contract and before consummation: their wife is immediately separated from them, and she is not permissible for them except with a new contract, according to the majority of jurists. Sheikh al-Islam Ibn Taymiyyah held that there is no difference between apostasy before or after consummation, and that if the apostate returns to Islam and the spouses desire to continue the marriage, they remain on their original marriage. He based this on the principle that the marriage originally remains valid and that the Prophet, peace and blessings be upon him, did not separate a man from his wife if one of them embraced Islam before the other. The Prophet, peace and blessings be upon him, returned Zaynab to Abu al-As ibn al-Rabi' with the first marriage, and similarly Safwan ibn Umayyah. It is more prudent to renew the contract.