Humaid bin Abdur Rahman narrated from his father that the Messenger of Allah (peace be upon him) was asked about «﴿قُلْ هُوَ اللّٰهُ أَحَدٌ﴾», so he (peace be upon him) said: "It is one third of the Qur'an," or, "It is equal to one third of the Qur'an."