What is the secret behind the mention of the number seven (such as seven heavens, seven days, seven whom Allah shades) and the number three (such as three in whom they are found, seeking permission thrice, triple divorce) in the Qur'an and Sunnah?

The peculiarity of the number seven has been clarified in previous fatwas. As for the number three, no distinct peculiarity has been mentioned for it in the available books, except that it is odd (witr), and it has been reported that "Indeed, Allah is Witr (Odd) and loves witr."