Musnad Ahmad 1013:75

Hashim ibn al-Qasim narrated to us, Abd al-Rahman—meaning Ibn Abd Allah ibn Dinar—narrated to us, from Abu Hazim, from Sahl ibn Sa’d al-Sa’idi, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "A day of guarding the frontier in the way of Allah is better than the world and what is upon it. And a journey that a servant makes in the way of Allah, whether in the evening or the morning, is better than the world and what is upon it. And the space of one of your whips in Paradise is better than the world and what is upon it."