Say ‘God is more knowledgeable of how long they tarried more knowledgeable than those contending over this issue — and this fact has already been mentioned above verse 19. To Him belongs the Unseen of the heavens and the earth that is to Him belongs the knowledge thereof. How well He sees! namely God — this form is for expressing amazement at something. How well He hears! likewise for expressing amazement. These two expressions are being used metaphorically. What is meant is that nothing can escape God’s sight or hearing. They the inhabitants of the heavens and the earth have no guardian someone to assist them besides Him and He makes none to share in His rule’ for He is Independent without need of a partner.