William Burkitt on Hebrews 5:11

That is, of which priesthood of Christ, as compared with Melchizedek, we have much to say, which is not easy to make intelligible by words, to those that are ignorant and dull of understanding.

Learn hence, 1. That all Scripture truths are not equally easy to be understood, but require a peculiar diligence in our attendance upon them, that they may be understood.

Learn, 2. That it is the incapacity of hearers, through dullness and slothfulness, and want of preparatory knowledge, which makes Scripture teaching no more and no better understood. All our miscarriages under the Word, are to be resolved into our own sloth, negligence, and depraved affections; We have many things to say, but ye are dull of hearing.