﴿ يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا۟ مَا لَكُمْ إِذَا قِيلَ لَكُمُ ٱنفِرُوا۟ فِى سَبِيلِ ٱللَّهِ ٱثَّاقَلْتُمْ إِلَى ٱلْأَرْضِ ۚ أَرَضِيتُم بِٱلْحَيَوٰةِ ٱلدُّنْيَا مِنَ ٱلْءَاخِرَةِ ۚ فَمَا مَتَٰعُ ٱلْحَيَوٰةِ ٱلدُّنْيَا فِى ٱلْءَاخِرَةِ إِلَّا قَلِيلٌ ﴾

“O YOU who have attained to faith! What is amiss with you that, when you are called upon, "Go forth to war in God's cause," you cling heavily to the earth? Would you content yourselves with [the comforts of] this worldly life in preference to [the good of] the life to come? But the enjoyment of life in this world is but a paltry thing when compared with the life to come!”

(O ye who believe! What aileth you that when it is said unto you: Go forth in the way of Allah�) [9:38]. This verse was revealed to prompt the believers to take part in the Battle of Tabuk. When the Messenger of Allah, Allah bless him and give him peace, returned from al-Ta'if and the Battle of Hunayn, he gave orders to attack the Byzantines. This happened at a time when people were living in straitened circumstances, the land was suffering from drought; it was very hot and it was time to reap the dates which were by then ripe. People found it very hard to conquer the Byzantines; they preferred to stay at home and enjoy the shade. The idea of going out to fight was very hard to accept. When Allah knew people's slackness, He revealed this verse.