'Abdullah ibn 'Umar reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "The best of companions in the sight of Allah Almighty is the one who acts best towards his companion. The best of neighbours in the sight of Allah Almighty is the one who acts best towards his neighbour."

Riyadh-as-Saliheen by Imam Al-Nawawi, volume 2, hadith number 311 - Sunni Hadith