Why Yahya bin Zakariyya (peace be upon them both) was called a master and chaste

It is narrated from Sayyiduna Amr bin al-As (may Allah be pleased with him) that he heard the Messenger of Allah (peace and blessings be upon him) say: "On the Day of Resurrection, all the children of Adam will come with some sin or other upon them, except Yahya bin Zakariyya (peace be upon him)." Then the Messenger of Allah (peace and blessings be upon him) stretched his hand down towards the ground and picked up a small stick (twig), and said: "That is because what men have (desire) was, in his case, only like this small stick (next to nothing); and that is why Allah named him 'a master', 'chaste' (abstinent) and 'a prophet from among the righteous'."
This hadith is sahih (authentic) on the condition of Imam Muslim, but the two Shaykhs (Bukhari and Muslim) did not record it.

It is narrated from Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) that the soul of Isa bin Maryam (peace be upon him) was one of those souls from whom a firm covenant was taken in the time of Adam (peace be upon him) (at the time of the Covenant of Alast). Then Allah sent it to Maryam (peace be upon her) in the form of a complete human being. She said: How can I have a boy when no human being has touched me and I have not been unchaste? Then that (soul) which was speaking to her entered (her womb) by way of her mouth (and she conceived).
This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.

It is narrated from Sayyiduna al-Bara' bin Azib (may Allah be pleased with him) concerning this saying of Allah Almighty: "Your Lord has placed beneath you a stream" [Surah Maryam: 24], that it refers to a small channel or a small river.
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) concerning this saying of Allah Almighty: "And We brought him near for private conversation" [Surah Maryam: 52], that (Sayyiduna Musa, peace be upon him) heard the scratching of the Pen at the time when (the decrees of destiny) were being written on the Preserved Tablet.
This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) concerning this saying of Allah Almighty: "And mention in the Book Ibrahim; indeed, he was a man of truth and a prophet" [Surah Maryam: 41], that the prophets were all from the Children of Israel except ten: Nuh, Salih, Hud, Lut, Shu'ayb, Ibrahim, Isma'il, Ishaq, Ya'qub and Muhammad (peace be upon them all); and among the prophets, only two had two names each: Isra'il (whose other name is Ya'qub) and Isa (whose other name is al-Masih).
This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.