The following is taken from the commentary on the January 20th entry in Consuming Fire, the daily devotional version of Unspoken Sermons by George MacDonald.

I believe we far too frequently mistake milk for meat, and get overly satisfied with the belief that we understand various principles as well as they can be understood, or at least as well as we need to.  As George MacDonald put it:  "Nothing is so ruinous to progress in which effort is needful, as satisfaction with apparent achievement; that ever sounds a halt".

Aside from our own satisfaction (a form of pride), firm insistence from others can lead us to falsely believe that we have come to a dead-end of what can be known. Quoting again from George MacDonald: "The babes must beware lest the wise and prudent come between them and the Father. They must yield no claim to authority over their belief, made by man or community, by church any more than by synagogue. That alone is for them to believe which the Lord reveals to their souls as true; that alone is it possible for them to believe with what he counts belief. The divine object for which teacher or church exists, is the persuasion of the individual heart to come to Jesus, the spirit, to be taught what he alone can teach."

All of us require, especially in spiritual matters, learning by degrees.  We must grow our spirits to be in harmony with what we know before we can properly understand more.  Indeed often before we even know what the next question is - or even that there is a next question.  Jesus knew this, and taught the apostles and disciples of his time in a "precept upon precept" manner.  George MacDonald reminds us that we are meant to be hungry for more knowledge and more righteousness: "God made man, and woke in him the hunger for righteousness; the Lord came to enlarge and rouse this hunger. The first and lasting effect of his words must be to make the hungering and thirsting long yet more."

The apostles then taught in similar manner (though perhaps with less patience), even explicitly noting such to the learners:

1 Corinthians 3:1-2: And I, brethren, could not speak unto you as unto spiritual, but as unto carnal, even as unto babes in Christ. I have fed you with milk, and not with meat: for hitherto ye were not able to bear it, neither yet now are ye able.

Hebrews 5:11-14: Of whom we have many things to say, and hard to be uttered, seeing ye are dull of hearing. For when for the time ye ought to be teachers, ye have need that one teach you again which be the first principles of the oracles of God; and are become such as have need of milk, and not of strong meat. For every one that useth milk is unskilful in the word of righteousness: for he is a babe. But strong meat belongeth to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil.

Thus we may conclude that much of what we read in the Bible is milk, though of course the teachings of our Lord were presented in such a way that we can find meat in the same words that have previously provided us with milk.

As we grow spiritually (as our faith increases), and we seek meat on various topics, we are likely to find that some questions are not directly answered in scripture. This can create moments (or more than moments!) of fear, and doubt.

Thus our spiritual growth has four notable and interconnected enemies: fear, doubt, pride, and oppression. About these enemies, George MacDonald has written much. Here are a few additional quotes relevant to this discussion:

"there is nothing that kills faith sooner than pride."

"all fear is sin, and one of the most oppressive sins from which the Lord came to save us."

“Doubts are the messengers of the Living One to rouse the honest heart. They are the first knock at our door of things that are not yet, but have to be, understood.”

The Lord wants us - indeed commands us - to grow in faith and increase in spiritual understanding. As such He provides us ample means, along with instructions of how to do so: prayer, love and obedience - along with testimony provided by the Holy Spirit.

John 7:17: If any man will do his will, he shall know of the doctrine, whether it be of God, or whether I speak of myself.

Matthew 7:7-8: Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you: For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened.

James 1:5-6: If any of you lack wisdom, let him ask of God, that giveth to all men liberally, and upbraideth not; and it shall be given him. But let him ask in faith, nothing wavering.

George MacDonald has written more about obedience than perhaps any other topic:

"What in the heart we call faith, in the will we call obedience."

"Wherever people speculate instead of obeying, they fall into endless error."

"Faith and obedience are one and the same spirit, passing as it were from room to room in the same heart: what in the heart we call faith, in the will we call obedience. [The] Lord refused absolutely the faith that found its vent at the lips in the worshipping words, and not at the limbs in obedient action"

"Faith in God is life and righteousness—the faith that trusts so that it will obey—none other. Lord, lift the people thou hast made into holy obedience and thanksgiving, that they may be glad in this thy world."

"It matters little where a man may be at this moment; the point is whether he is growing. The next point will be, whether he is growing at the ratio given him. The key to the whole thing is obedience , and nothing else. The whole secret of progress is the doing of the thing we know. There is no other way of progress in the spiritual life; no other way of progress in the understanding of that life; only as we do, can we know. Obedience is the soul of knowledge."

Often we know of something we must be obedient to, yet lack the faith and courage to do it. In such cases we must take the first steps. As we do so, the Lord's Grace will fill our souls with courage and understanding - sufficient enough at least to make the next step or two, and so forth. In The Marquis of Lossie, the following relevant conversation occurs:

"Faith is obedience, not confidence."

"Then I do well to fear."

"Yes, my lady, so long as your fear makes you knock the louder."

"But if I be in, as you say, how can I go on knocking?"

"There are a thousand more doors to knock at after you are in, my lady. No one content to stand just inside the gate will be inside it long. But it is one thing to be in, and another to be satisfied that we are in. Such a satisfying as comes from our own feelings may, you see from what our Lord says, be a false one. It is one thing to gather the conviction for ourselves, and another to have it from God. What wise man would have it before he gives it? He who does what his Lord tells him, is in the kingdom, if every feeling of heart or brain told him he was out. And his Lord will see that he knows it one day. But I do not think, my lady, one can ever be quite sure, until the king himself has come in to sup with him, and has let him know that he is altogether one with him."

Love is godliness, and also an essential form of obedience, and as such one of its blessings is knowledge:

"To the loving soul alone does the Father reveal Himself; for love alone can understand Him. It is the peace-makers who are His children."

As we act in obedience and love, the Holy Spirit can purify and enlarge our hearts, minds and spirits - thus increasing our capacity for faith, and filling it.

Prayer is perhaps the greatest of all tools for increasing our faith and understanding. We are encouraged to put it to use: "If any of you lack wisdom, let him ask of God". Perhaps the greatest question we can pose is: "What lack I yet?" - what more do I need to do or learn or give up?

To be able to talk to God through prayer - knowing that he is eager to give ("For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened") is a grand opportunity indeed. George MacDonald expressed his feelings of it this way:

"the highest and loveliest, the most entrancing privilege of existence, that of pouring forth my whole heart into the heart of him who is ACCOUNTABLE FOR me, who hath glorified me with his own image"

Finally, George MacDonald reminds us that "The principle part of faith is patience"; however, as we submit to His will, pray for his assistance, and do our best to obey, we may find ourselves -

"Partakers thus of the divine nature, resting in that perfect All-in-all in whom our nature is eternal to, we walk without fear, full of hope and courage and strength to do His will, waiting for the endless good which He is always giving as fast as He can get us able to take it in."