What is the ruling on marrying a second wife who helps one obey God, despite not having the financial means, especially since the first wife is not interested in learning jurisprudence?

It is an individual obligation upon the wife to learn the amount of knowledge by which her creed becomes sound and her obligatory acts of worship become valid. Learning the details of the Islamic sciences is a communal obligation (fard kifayah). Do not be overly strict with her in seeking knowledge, for that may lead to discord. Polygyny is permissible for one who can be just, and it may be more beneficial to be content with one wife if she is righteous.