Maturity and maturity of a person when he reaches the maturity of the mind, ie when his head has reached a certain shape and no longer experience the process of enlargement or shrinking.
Described in the book 'Science in the Qur'an' written Nadiah Thayyarah, in general human skull consists of bones that are interconnected with each other, as well as closely related and strong. Among the bones, there is a soft cartilage that strengthens.
The cartilage will gradually get stronger over time. When humans reach the age of 40 years, this cartilage becomes the perfect level of violence. It will grow and will refine the skull structure so that it affects the mind core located in the brain.
"We commanded men to do good to his two mother-mothers, his mother was hard-earned, and gave birth to him with difficulty." To bear it until weaning was thirty months, so that when he was an adult and until the age of forty he pray:
"O my Lord, show me to be grateful for the blessings you have given me and to my father's mother and so that I can do righteous deeds that You are pleased with me to grant favor to my children.
Verily I repent unto Thee and verily I am among those who surrender, "says Surah Al Ahqaf Verse 15. The verse states the importance of the age of 40 years in human life, so prophethood comes to the prophets when they are 40 years old.