Why is birth control considered unlawful except out of necessity, while abstaining from marriage is not unlawful, even though abstaining from marriage means abstaining from procreation?

First: Birth control is forbidden except in cases of proven necessity, such as harm to the mother based on the report of a trustworthy Muslim physician. It is permissible to regulate or postpone it for a valid interest. However, preventing pregnancy for fear of poverty or for unlawful reasons is forbidden.

Second: Marriage may not be obligatory in principle, but if a person marries, some actions become forbidden to him, such as divorce without cause according to some scholars. The distinction between the initiation and continuation of a ruling is present in Islamic jurisprudence, and the principle "What is excused in continuation is not excused in initiation" applies here.