Prophet Zakariya (alayhis-salam) said, “And indeed, I fear [what my] successors [will do] after me, and my wife has been barren, so grant me a successor–a gift from You–to be my heir (in religion) and the heir of the family of Ya’qub. Lord, make him well pleasing [to You].” [Surat Maryam: 5-6]
A reflection: Allah shows us the primary purpose for wanting to have children through the dua of Prophet Zakariya. That is, to pass on the religion, worship of the Creator, and knowledge of Islam down to our children.
Not just ‘down to our children’ but then by them ‘on’ to others. It links with the Prophet (S)’s saying:
اكثروا الاوﻻد فاني مكاثر بكم الامم يوم القيامة
Make many your children – because by you I (my people) will exceed the other peoples on the Day of Qiyaama.
او كما قال صلى الله عليه وسلم