It can also mean their gradual lengthening and contraction...

It can also mean their gradual lengthening and contraction, which result in the four seasons of the year and are important factors in the life of the plants. These factors all serve to guide us to knowing and thanking Allah.

Thus, at the end of the verse it says: “...Have you then no sense?” Some Traditions On the Intellect The Prophet (S) said: “Intellect is something by which Paradise will be detained and through which the pleasure of Allah is achieved.” [^1] Imam Ali (as) said: “The intellect guides and ignorance misleads.” [^2] Imam Ali (as) said: “Allah, the Glorified, has not distributed anything better than the intellect among His servants.” [^3] Imam Hassan al-Mujtaba (as) said: “By means of the intellect one can achieve both the goodness and reward of this world and the Hereafter and the one who has no intellect is deprived of the benefits and advantages of them all together.” [^4] Imam Rida (as) said: “The intellect is the friend of every man, and his enemy is his ignorance.” [^5] Imam Ali (as) said: “One cannot overcome the world except by the power of the intellect.” [^6] The Prophet (S) said: “Man’s religion is his intellect and whoever has no intellect has no religion.” [^7] Imam Sadiq (as) said: “Pondering much on science (and knowledge) opens the gate of the intellect.” [^8] The Prophet (S) said: “Everything has a tool (and a support), and the believer’s tool (and support) is the intellect.

Everything has a vehicle and man’s vehicle is the intellect. Everything has an end and the end of worship is the intellect. Every nation has a guardian and the guardian of the worshippers is the intellect. Every merchant has a capital and the capital of the strivers is the intellect. Everything ruined is mended by something and the Hereafter is mended by the intellect.