Why do we supplicate to Allah, even though all His commands are good, and His decrees are good, even if we do not supplicate?

Supplication (Du'a) is part of divine decree (Qadar (definition)) and a means to goodness and mercy. It is not permissible to abandon it under the pretext that the divine decree is inevitable, for Allah has linked causes to their effects. The verses of the Quran and the Sunnah (definition) have encouraged supplication, as it indicates one's dependence on Allah. It is Allah's practice to test with both good and evil, and the wise person resorts to Allah through supplication to escape a painful decree to a suitable one. This was the practice of the Prophets and the righteous, as seen in the stories of Ayyub (Job), Yunus (Jonah), and Zakariyya (Zachariah), peace be upon them, and the supplication of the Prophet, peace be upon him, and his Companions on the Day of Badr. This confirms that supplication does not contradict the fact that both good and evil are from Allah and for a wise purpose.