שמואל ב ג׳:ב׳-ה׳

ומשנהו כלאב. ובמקום אחר הוא קורא אותו ומשנהו דניאל, ולמה נקרא שמו כלאב, אמר רבי יצחק: שהיו ליצני הדור אומרים, מנבל היתה אביגיל מעוברת, נהפך קלסתרו ונדמה לאביו. ורבותינו אמרו (ברכות ד א): שהיה מכלים פני מפיבושת בהלכה:

His second [son] was Kilov. [But] in another place¹Divrei Hayomim I, 3,1. [Scriptures] calls him, "and his second [son] was Doniel".²i.e., refers to the second son of Dovid not as Kilov but as Doniel, his true name. So why is his called [here] by the name of Kilov? Rebbe Yitzchok said [to answer this question] : Because the generation's cynics were saying that Avigail was pregnant from Novol,³That Doniel was the son of Novol and not Dovid. [consequently Hashem caused] his facial features to change and resemble his father.⁴His resemblance to Dovid earned him the name of כִלְאָב a play on כּוּלוֹ אָב, “completely his father.” And our Rabbis said⁵Berochos 4a. that [this name of Kilov was due to the fact that] he embarrassed Mephiboshes through Halacha.⁶Doniel’s superior knowledge became evident during the course of his halachic debates with Mipiboshes. According to this Derosho, the letters כל of כִלְאָב stand for מַכְלׅים.

לעגלה. זו מיכל, שהיתה חביבה עליו, וכן הוא אומר (שופטים יד יח): לולא חרשתם בעגלתי. והכתיב (לקמן ו כג): ולמיכל בת שאול לא היה לה ולד עד יום מותה, עד יום מותה לא היה לה מאותו מעשה ואילך, קודם אותו מעשה הוי לה:

By Egloh This refers to Michal⁷The daughter of Shaul. who was cherished by him. Similarly it says "If you had not plowed with my calf" (Shoftim 14, 18).⁸עגלה, “calf” is used in reference to a cherished wife just as a calf is cherished by it’s owner (See Sanhedrin 21a). [But] it is written, "And Michal, the daughter of Shaul had no child until the day of her death" (Below, 6, 23) she didn't have one until the day of her death⁹At which time she died in childbirth (ibid).?¹⁰That verse implies that Michal had no children up to the time of her death, but our verse states that Egloh, i.e. Michal gave birth to Yisrom. From that incident¹¹Dovid rejoiced excessively when the Ark was returned from captivity. Michal rebuked Dovid for what seemed to her to be behavior beneath his dignity. This was not the case and she was punished for the unwarranted shaming of Dovid. (ibid). and on [she had no children], but prior to that incident she did have [children].