Then He clarified the reason for His guidance to avoid them by what He is not able to convey of the good tidings and warning, that they have not deviated from His will, glorified and exalted is He. And that faith cannot be entered into their hearts by anyone other than Him. So He said, "Indeed, we do not do that because we have made what is on the earth of the three progeny: animals, minerals, and plants, a decoration for it by making it beautiful in the eyes and delighting the souls with it. If it were not for the harm of the harmful animals from insects and others, the decoration would be apparent. It is evident that if all the people obeyed, its harm would have gone and its beauty would have appeared, just as it will be in the time of Jesus, blessings and peace be upon him, when it becomes a plaything for children.

And when He informed about its beautification, He informed about its reason. So He said, "To test them," meaning to deal with them as the tester who asks due to the obscurity of the matter upon him, by His saying, "Which of them is best in deed?" meaning with the sincerity of service to his Lord. Thus, what we used to know of them becomes apparent through action. The proof is established against them regarding what they recognize among themselves, that whoever shows agreement with the matter in what he has obtained from the decoration earns the reward, and whoever dares to oppose the matter with what We have given him from it, acting as if it is solely for enjoyment, has deserved punishment. And when the call of decoration to the reality of worldly life is evident as it aligns with what the souls are inclined to from desires, there was no need for further indication other than the word decoration.