(158) It is related by Abu Moosa that the Apostle of God said: “Whoever makes the world his mistress shall incur the loss of the Hereafter, and whoever makes the Hereafter his mistress shall incur the loss of the world. Thus, [when between the world and the Hereafter the choice of one is sure to lead to the loss of the other, you ought to] choose the Hereafter.”
-Musnad-i-Ahmad and Baihaqi
Commentary.-When a person will make the world the exclusive aim of his life, he will live for it and all his endeavours will be directed towards the realisation of material aims and interests and the Hereafter will get into the background: he will not care much for it, and eventually, it will lead to the loss of the world to come.
Similarly, when a person will set his heart on the Hereafter he will strive for it to the best of his ability, and his worldly interests will suffer in the outcome. Hence, a truthful Believer should make the Hereafter the object of his desire, which is eternal. The material world, at the best, is a nine days' wonder.