All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The view that we adopt here in Islamweb is that the conditional divorce takes place when the condition that is made for divorce happens. This is whether it is intended to initiate divorce, or it is intended to threaten or affirm and the like, and this is the view of most scholars, including the four Imams .
Some scholars, such as Sheikh al-Islam Ibn Taymiyyah have argued that a conditional divorce that is for the purpose of threatening or emphasizing and not with the intention of effecting divorce does not take place, but it requires the person to expiate for breaking the oath.
Divorce during menstruation is effective according to most scholars, despite being an innovative divorce (i.e., not according to the Sunnah). Whoever initiates a conditional divorce on his wife when she is menses; his divorce takes place if the condition upon which he made divorce takes place whether it happened while she was in menses or pure. However, what is considered in whether the divorce was innovative or Sunni, is the time when divorce took place and not the time when it was made conditional.
Al-Ghazali said in Al-Waseet:
“If the divorce was made conditional just upon her coming, and she came while she was in menses, then an innovative divorce takes effect. If it is not in the state of a conditional divorce according to the people of Sunnah and innovation, what is considered is the state when the divorce took place, not at the time when the divorce was made conditional.” [End of quote]
Accordingly, if your wife disagreed with you and did not pray, the view that we adopt here in Islamweb is that divorce took place, and if that divorce was not the third divorce; you can take your wife back during her waiting period.
As for the saying of Sheikh al-Islam Ibn Taymiyyah, may Allaah the have mercy upon him, your divorce does not take place as long as you did not intend to initiate it with this condition, but you are required to expiate for breaking the oath.
Breaking of this oath depends on your intention with what you uttered in your oath. The intention in the oath specifies the general and restricts the absolute. If you intend a specific prayer or a specific time, and your wife disagreed with you in that, then you broke your oath, otherwise; there is no breaking of the oath.
Noting that if you conditioned the divorce of your wife if she did not pray immediately, and she did not pray because she was menstruating; then the most correct view in our opinion, in this case, is that you did not break your oath.
Ibn al-Qayyim said in I'lam al-Muwaqqi’een: “What fits the rules and principles of Ahmad is that one does not break the oath when it is not possible to achieve the matter upon which he conditioned divorce, whether the inability was due to a legitimate prohibition, or a predestined universal prohibition, as is his [Ahmad’s] opinion if the inability was due to coercion.” [End of quote]
Moreover, you have to order your wife to pray and show her the greatness of its value and its position in Islam, for prayer is the most important matter of religion after faith. There is no share in Islam for those who leave it. You have the right to discipline her for not praying.
Ibn Qudamah said in Al-Mughni:
“He has the right to discipline her for abandoning the ordinances of Allah. Ismail ibn Sa’eed Ahmed was asked about matters on which it is permissible for a woman to be beaten, and he said: ‘For abandoning the ordinances of Allah.’ He also said about a man who has a wife who does not pray: He beats her gently and not severely.’” [End of quote]
For more benefit on conditional divorce, please refer to Fatawa 373048, 370447, 355693, 352696 and 328318.
Allah knows best.