Hadith: Whoever dies without having fought (in the cause of Allah) or having thought of fighting (in the cause of Allah) will die while having one of the qualities of hypocrisy

عن أبي هريرة رضي الله عنه مرفوعاً: «من مات ولم يَغْزُ، ولم يُحدث نفسه بالغزو، مات على شُعْبَةٍ من نِفَاقٍ»
[صحيح] - [رواه مسلم]

Abu Hurayrah (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: “Whoever dies without having fought (in the cause of Allah) or having thought of fighting (in the cause of Allah) will die while having one of the qualities of hypocrisy.”
[Authentic hadith] - [Narrated by Muslim]

Explanation

Any man who dies although he was capable of fighting in the cause of Allah but neither fought nor had the intention to do so, has something of hypocrisy. The intention is proved by preparing the gear needed for fighting. Allah, the Almighty, says: {And if they had intended to go forth, they would have made some preparation for it} [Sūrat At-Tawbah: 46]. Whoever dies in this state is similar to the hypocrites and laggers who do not take part in Jihad. Since whoever imitates a category of people does belong to them, therefore every believer must have the intention of making Jihad.