Is it permissible for a wife to return to the old marriage contract after her divorce, based on the legal seclusion (khalwa shar'iyya) in which consummation did not occur, or must there be a new contract and dower?

The majority of scholars hold that divorce before consummation is a talaq bain (irrevocable divorce), even if seclusion occurred, as long as neither party claims that intercourse took place. As for the Hanbalis, they are of the opinion that valid seclusion has the ruling of consummation, so the woman is not irrevocably divorced by the first talaq, and the husband may take her back during her iddah (waiting period) without a new contract. Therefore, your taking back of your wife without a new contract is valid according to the Hanbalis, and this is the view that we follow in our fatwas.