The important lesson to understand from this hadith is that we must not fear death, loss or reproach in obeying the commands of Allah (subhana wa ta’ala), for only that harm will come to us which is already destined to. A believer should not be frightened by the number or resources of the enemies of Allah. This should never determine whether they should obey Allah or not, as this hadith tells us that they can not do any harm unless Allah has destined it for them. And if that is the case that harm will come anyway, but the believer will be rewarded for obeying the commands of Allah (subhana wa ta’ala).
Unfortunately, we find Muslims helping to hurt and kill other Muslims today, using as an excuse that harm would come to them otherwise. We need to develop our understanding of qada wal qadar to become righteous.
This hadith has been sent to me by dailyhadith.