Anas ibn Malik reported: The Messenger of Allah, peace and blessings be upon him, said:

عَلَيْكَ بِحُسْنِ الْخُلُقِ وَطُولِ الصَّمْتِ فَوَالَّذِي نَفْسُ مُحَمَّدٍ بِيَدِهِ مَا عَمِلَ الْخَلائِقُ عَمَلا أَحَبَّ إِلَى اللَّهِ مِنْهُمَا

You must have good character and observe long periods of silence. By the one in whose hand is the soul of Muhammad, no one can behave with deeds more beloved to Allah than these two.

Source: al-Mu’jam al-Awsaṭ 7287, Grade: Jayyid