Allah’s cause, yet some of you withhold. Whoever withholds does so only to his own detriment. Allah is free of need, while you are in need. If you turn away, He will replace you with another people, who will not be like you.”
Surah Muhammad, 38

Through courage and generosity in His cause, Allah gave precedence to those who came first. He says:

“Those of you who spent and fought before the conquest are not equal to those who did so afterwards. They are greater in rank than those who spent and fought afterwards. Yet Allah has promised each the finest reward.”
Surah al-Hadīd, 10

He has mentioned and praised striving in His cause with one’s life and wealth in numerous verses of His Book. This is courage and generosity in obedience to Him, glorified be He, and to His Messenger. The foundation of courage is steadfastness, which entails strength and firmness of heart. Thus He, exalted be He, says:

“How many a small force has overcome a large force by Allah’s permission! And Allah is with the steadfast.”
Surah al-Baqarah, 249

And He, exalted be He, says:

“O you who believe, when you encounter an enemy force, stand firm