Musnad Ahmad 27:350

Waki’ narrated to us, from Sufyan, from Mansur, from Salim ibn Abi al-Ja’d, from Yazid ibn Bishr, from Ibn Umar, who said: "Islam was built upon five: the testimony that there is no god but Allah, the establishment of prayer, the giving of zakat, the pilgrimage to the House, and the fasting of Ramadan." A man said to him: "And jihad in the way of Allah?" Ibn Umar said: "Jihad is good, [but] thus did the Messenger of Allah, may Allah bless him and grant him peace, narrate to us."