Al-Shafi'i said in one of his two opinions: If he intends by the Khul' a divorce and names it, then it is a divorce. If he neither intends a divorce nor names it, no separation occurs; he stated this in the Qadim (the old school).
Abu Thawr said: If he does not name divorce, then the Khul' is a separation and not a divorce. If he names a divorce, then it is a single divorce, and the husband has the right to take her back as long as she is within her waiting period (iddah).
422: 2227: With the Sunnah: 1: It was narrated from Ibn 'Umar—may Allah be pleased with them both—from the Prophet, peace and blessings of Allah be upon him, regarding a man who marries a woman and divorces her before he has consummated the marriage with her completely (albata), then another man marries her and divorces her before he has consummated the marriage with her; does she return to the first? He said: "No, until she tastes his 'usaylah (metaphor for intimacy) and he tastes her 'usaylah."
Authentic. It was narrated by al-Bukhari (7/55), Muslim (h/1057), al-Nasa'i (6/146), al-Fath (9/469), and Ahmad (2/62, 193).
424: 2240: With kindness: 1: I say: The retention here refers to returning to the bond of marriage with kindness. This means he bears witness to taking her back and intends to live with her in kindness, or he releases her, meaning: he leaves her until her waiting period ends and he lets her leave his house in a manner that is better, without dispute or abuse.
425: 2246: To cause harm: 1: Al-Qurtubi said: Malik narrated from Thawr ibn Zayd al-Daylami that a man would divorce his wife then take her back, even though he had no need for her and did not intend to retain her, just to prolong the waiting period for her and to harm her.