Where in the Quran is Ghusl stated?

In what ayah(s) does it state that we need to perform Ghusl, for what occasions, and why? I understand that the Quran talks about religious purity, but it never explains how to recover from religious impurity. The reply I am looking for would only consist of Quran references; please refrain from answers that rely on hadiths or third-party explanations of God's verses.