Had He taken a son

If Allah had intended to take a son, He could have chosen from what He creates whatever He willed. Exalted is He; He is Allah , the One, the Prevailing.

[Qur'aan 39:4]

Imaam al-Tabari writes:

Allaah says: Had Allaah Willed to take on a son, while that is not fitting for Him to do so, He would have raised from that which He has created what He Willed. He says: Allaah is above [far to superior] to have a son and free and above that which the polytheists ascribe to him of their polytheism. He is the One, everything worships and had He had a son he would not have been a slave to Him [so it is not possible for Him to have a son because everyone is His slave]. He owns everything so how can their be a son to Him. He is the One who has no partner in His Dominion and Power and all of the Creation is subjugated to Him. Everything is humbled before Him.

وقوله: ( لَوْ أَرَادَ اللَّهُ أَنْ يَتَّخِذَ وَلَدًا ) يقول تعالى ذكره: لو شاء الله اتخاذ ولد, ولا ينبغي له ذلك, لاصطفى مما يخلق ما يشاء, يقول: لاختار من خلقه ما يشاء. وقوله: ( سُبْحَانَهُ هُوَ اللَّهُ الْوَاحِدُ الْقَهَّارُ ) يقول: تنـزيها لله عن أن يكون له ولد, وعما أضاف إليه المشركون به من شركهم ( هُوَ اللَّهُ ) يقول: هو الذي يَعْبده كلّ شيء, ولو كان له ولد لم يكن له عبدا, يقول: فالأشياء كلها له ملك, فأنى يكون له ولد, وهو الواحد الذي لا شريك له في ملكه وسلطانه, والقهار لخلقه بقدرته, فكل شيء له متذلل, ومن سطوته خاشع