Regarding the verse "And We have enjoined on man to be dutiful and kind to his parents. His mother bears him with hardship. And she brings him forth with hardship, and the bearing of him, and the weaning of him is thirty months, till when he attains full strength and reaches forty years, he says: "My Lord! Grant me the power and ability that I may be grateful for Your favour which You have bestowed upon me and upon my parents, and that I may do righteous good deeds, such as please You, and make my offspring good. Truly, I have turned to You in repentance, and truly, I am one of the Muslims" [46:15]. How do we fulfill the rights of the parents even we are very far from them like staying in another country? Also, why did Allah عز وجل mention the age of forty?