O you who have believed, do not be like those who disbelieved and said about their brothers when they traveled through the land or went out to fight, "If they had been with us, they would not have died or have been killed," so Allāh makes that [misconception] a regret within their hearts. And it is Allāh who gives life and causes death, and Allāh is Seeing of what you do.
O you who have faith in Allah and follow His Prophet, do not be like those among the hypocrites who disbelieve, who do not have faith in destiny and Allah’s decree, and who say of their relatives if they travel to earn a living or go out to fight and they die or are killed: If they had stayed with us, and not gone or not fought, then they would not have died or been killed. Allah makes this belief in their hearts increase their regret. Allah alone gives life and death as He wills: staying behind would not stop His decree, and going would not bring it more quickly. Allah sees what you do. None of what you do is hidden from Him and you will be rewarded according to what you do.