Hadith: Observing Ribāt (guarding the Muslims' frontiers) for one day in the way of Allah is better than the world and everything therein.

عن سهل بن سعد رضي الله عنه مرفوعًا: «رِبَاطُ يَوْمٍ فِي سَبِيلِ الله خَيْرٌ مِنْ الدُّنْيَا وَمَا عَلَيْهَا، وَمَوْضِعُ سَوْطِ أَحَدِكُمْ فِي الْجَنَّةِ خَيْرٌ مِنْ الدُّنْيَا وَمَا عَلَيْهَا، وَالرَّوْحَةُ يَرُوحُهَا الْعَبْدُ فِي سَبِيلِ الله وَالْغَدْوَةُ خَيْرٌ مِنْ الدُّنْيَا وَمَا فِيهَا».
[صحيح] - [متفق عليه]

Sahl ibn Sa‘d (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "Observing Ribāt for one day in the way of Allah is better than the world and everything therein. A place in Paradise as small as that occupied by the whip of one of you is better than the world and everything therein. A morning's or an evening's journey that one travels in the way of Allah is better than the world and everything therein.”
Sahih/Authentic. - [Al-Bukhari and Muslim]

Explanation

The Prophet (may Allah's peace and blessings be upon him) informed us that three things are better than this world and everything therein: observing Ribāt for one day in the way of Allah, traveling in the way of Allah, and the very little space that one gets in Paradise that is equal to the space occupied by one's whip. This is because Paradise is everlasting, whereas this world is transitory, and a little of what is eternal is better than a lot of what is perishable.