What is the ruling on abandoning the study of medicine and devoting oneself to seeking sacred knowledge, knowing that the parents desire the study of medicine and there is no need for money?

Seeking sacred knowledge is the best and most beneficial of sciences in this world and the hereafter. If your father does not object to you leaving what he desires and specializing in what you want, then do what you want. But if he is not pleased with that, then do what he wants. Seeking knowledge in general is among the noblest of tasks and the best way for a servant to draw closer to Allah Almighty, and the best of sciences are the sciences of Sharia (definition).

So, if your father does not object to you dedicating yourself to seeking sacred knowledge, then this is a divine blessing from Allah Almighty and a good that He has brought to you. Therefore, approach it with diligence and a sincere intention for the sake of Allah Almighty.

However, if your father is not pleased with that, then obey your father if you believe you will succeed in studying medicine, and purify your intention, aiming through it to benefit Muslims. Your study will then be an act of worship. But if you feel that you cannot study medicine, then explain that to your father, hoping he might agree to what you want.

Know that obeying parents in what is good is obligatory. You should also continue, in parallel, to study what you need to know of the Sharia sciences.