Couple Organized Tahleel Marriage to Get Back Together and Had Children Afterwards
5-11-2020 | IslamWeb
Question:
Sheikh i know of a couple who divorced more than three times and they organised halala to get back together and despite telling them not to do that they ignored us and they got back together and they produced children from that marriage are they bastards the children kindly clarify
Answer:
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 Tahleel marriage is invalid according to the opinion of the majority of the jurists, and it is the view that we consider to be the most preponderant opinion because of the strength of the evidence.
The Prophet said: “Allah has cursed the man who marries a woman to make her permissible for the first husband, and He cursed the first husband [for being content with this].” [Ahmad and others]
If the two spouses do this, then they have committed a great sin, and the woman does not become permissible to her husband with this marriage.
As for the children, they are traced back to their father, because this marriage is of the kind of marriages upon which there is a difference of opinion regarding its validity.
Al-Bahooti, from the Hanbali School of jurisprudence, said in Kash-Shaaf al-Qinaa’: “The lineage [of tracing the children back to the father] is confirmed in a marriage upon which there is a difference of opinion about its validity, and also the ‘Iddah (waiting period) if he has consummated the marriage with her or was in seclusion with her, as well as the named Mahr (bridal money) if he has consummated the marriage with her, exactly like the valid marriage….” [End of quote]
[Definition of Tahleel marriage: it is the marriage in which a man marries a woman after she was divorced three times by her husband simply in order to make her lawful for her (first) husband to marry her again]
For more benefit on Tahleel Marriage, please refer to Fataawa 426517, 329044, 92332, 87878, and 134069 (for definition).
Allah knows best.