It was narrated from Ibn ‘Umar that a man said to him: “Why don’t you go out and fight?” He said: “I heard the Messenger of Allah صلی اللہ علیہ وآلہ وسلم a; say: ‘Islam is built on five (pillars): Testimony that there is none worthy of worship except Allah, establishing Salah, giving Zakah, Hajj, and fasting Ramadan.” (Sahih)