Ibn Majah

Benefits and Issues:

➊
The Banu Qurayza had made an agreement with the Muslims that they would not assist the Quraysh of Makkah against the Muslims. However, due to the instigation of Huyayy ibn Akhtab, the chief of Banu Nadir, the chief of Banu Qurayza, Ka‘b ibn Asad, became inclined towards breaking the covenant.
And during the Battle of the Trench (Khandaq), the Banu Qurayza practically aided the disbelievers and carried out actions that increased the difficulties for the Muslims.
Thus, this tribe, Banu Qurayza, became guilty of breaking the covenant.

➋
After the Battle of the Trench was over, the Prophet (sallallahu alayhi wa sallam) laid siege to the settlement of Banu Qurayza.
Allah, the Exalted, cast terror into their hearts, and they became willing to surrender their weapons and said that whatever decision Sa‘d ibn Mu‘adh (radi Allahu anhu) would make, they would accept it.
Sa‘d ibn Mu‘adh (radi Allahu anhu) ruled that all the men of Banu Qurayza should be killed, the women and children should be taken captive, and their wealth and belongings should be distributed among the Muslims.
For details, see: (Al-Raheeq Al-Makhtum, p. 509 to 512)

➌
The growth of pubic hair is a sign of puberty.

➍
The prescribed punishment (hadd) is not carried out on minors; however, an appropriate discretionary punishment (ta‘zir) may be applied.