Some traditions indicate that marriage is one of the reasons for the increase of sustenance, but this does not mean that it is a complete cause for it. There might be obstacles that prevent it or conditions of sustenance that are not met. On the other hand, Almighty God might limit one’s sustenance for various reasons, such as to test one's faith or increase one’s rewards if one is patient, or other reasons that we are ignorant of. So, we should always turn to Him in all our affairs and ask Him to provide us with what is lawful and what would be good for us. Asking forgiveness is one of the means to increase sustenance and thanking the Almighty for His bounties is one of the causes for the continuance of blessings, as the narrations indicate, so we must do what we can from that. In addition to this, one can recite supplications that help in sustenance, which are mentioned in the books of supplications. If the supplication is answered, we thank God for that. If it isn't, we have to be patient, as it is perhaps will be good for us.
