Why is evil easier than good?
Because good is an uphill path and evil is a downhill one. Good demands effort and responsibility, while evil is simply the absence of good and costs no strength. That is exactly why good is rewarded.
Throw a stone upwards. The heavier it is, the more strength you need. But it comes down entirely on its own. Good and evil work the same way. Good is an uphill path, evil a downhill one. That is why evil comes more easily and spreads more quickly.
Behind this lies a deeper thought. The Holy Qur’an does not set good and evil side by side as two equally strong powers. Good has a real, positive value of its own. Evil is rather its absence, just as darkness is not a thing in itself but only the absence of light. God has placed good qualities in human nature. When we neglect or misuse them, evil arises. Every virtue we lack leaves a gap behind.
Holding on to good takes work, because it brings responsibility with it, and responsibility is a load that has to be carried. Nothingness needs no effort. It is like standing still. That is why some people choose evil even though they have the choice. It is simply more comfortable.
An everyday example makes this clear. If someone tempts you to steal, your first thought is the quick gain. That is the downhill path. But if you say, this does not belong to me, you are climbing uphill. With that step you come closer to God in one of His attributes.
It is precisely because good is hard that it has value and is rewarded. If it were as easy as evil, it would be no achievement. The verses above speak of the ascent that man is meant to attempt. Whoever dares it and purifies his soul will succeed.