Richard Baxter in The Reformed Pastor urged pastors to spend time in evangelism, especially in instructing their own people to be sure not to lose one of their own church members. He then answered a number of objections that people may bring up.
Objection 3: This course of evangelism will take up so much time, that a man will have no opportunity to follow his studies. Most of us are young and inexperienced, and have need of much time to improve our own abilities, and to increase our own knowledge, which this course will entirely prevent.
Answer 1: I highly value common knowledge, and would not encourage any to set light by it; but I value the saving of souls more. That work which is our great end must be done, whatever be left undone. Men’s souls may be saved without knowing whether God did predetermine the creature in all its acts; whether the understanding necessarily determines the will; whether God works grace in a physical or in a moral way of causation; what freewill is; and a hundred similar questions, which are probably the things you would be studying when you should be saving souls. Get well to Heaven, and help your people thither, and you shall know all these things in a moment, and a thousand more, which now, by all your studies, you can never know; and is not this the most expeditious and certain way to knowledge?
Answer 2: You may have competent time for both evangelism and personal studies. Lose no time upon vain recreations and employments; consume it not in needless sleep; trifle not away a minute. Do what you do with all your might; and then see whether you have not competent time for these other pursuits.
Answer 3: If you must choose one duty above another, I there were such a case of necessity, that we could not carry on further studies, and instruct the ignorant too, I would throw aside all the libraries in the world, rather than be guilty of the perdition of one soul; or at least, I know that this would be my duty.
*These paragraphs are abridged from pages 213-215 in The Reformed Pastor by Banner of Truth.