Why was the bowing (rukuʿ) made once and the prostration (sujud) twice in prayer?

Allah, the Exalted and Most High, prescribed one bowing (rukūʿ) and two prostrations (sujūd) in each unit (rakʿah) of prayer. Jibril (Gabriel) taught this to the Prophet, peace and blessings be upon him, and the Prophet, peace and blessings be upon him, said: "Pray as you have seen me praying."

Al-Bahūtī, in "Kashshāf al-Qināʿ," mentioned the wisdom behind the repetition of prostration, stating that it represents the utmost humility. The prostration of the worshipper after standing and bowing is the ultimate act of servitude to Allah. Then, he prostrates a second time in gratitude for being singled out for this service and for being saved from the wiles of Satan.

Some acts of worship, such as the number of prayers and their units, and the number of pebbles (for stoning the jamarāt), are taʿabbudī (acts of pure devotion), meaning their underlying wisdom is not fully comprehensible to human intellect. Perhaps the wisdom behind them is to test the worshippers and gauge the extent of their absolute submission to the command of Allah, the Exalted.