But you are not to be called `Rabbi', for you have only one Master and you are all brothers. And do not call anyone on earth `father', for you have one Father, and he is in heaven. Nor are you to be called `teacher', for you have one teacher, the Christ. The greatest among you will be your servant. For whoever exalts himself will be humbled, but whoever humbles himself will be exalted. (Matthew 23:8-12)
Only one teacher!—and he is Christ. None of the rest of us can claim that status, which he reserves for himself. Yet for that very reason, all instruction which is true instruction must find its origin in him. Those of us who are earthly instructors must therefore recognize, that if there is any wisdom in what we say, it comes from the Son of God. We are not the teacher, but we allow God to be the teacher.
In every form of knowledge, there is both a spiritual opportunity: seeing Jesus as your teacher, and a spiritual danger: idolatry. Idolatry comes when we see ourselves or others as the teacher, and don't allow the knowledge to lead us onward to God. In some ways, the more noble the pursuit, the greater the danger of idolatry. When scientists are satisfied to learn about creation without learning about the Creator, Science becomes a mere distraction to occupy the mind. Maybe this is the real reason why fewer scientists than ordinary folk believe in God. Science is so interesting that one doesn't feel the need to investigate deeper questions . . . and so the opportunity for salvation slips by, unnoticed.
On the other hand, the spiritual opportunity is present no matter how "low" on the scale of spiritual values is the thing which is being taught. So long as the thing contains within itself something that is good, whether physical or mental, aesthetic or practical, there is a spiritual lesson to be had in it. Any craft demands that one humbly learn from some particular Reality what is the right way to approach it: the corollary is the need to repent of your bad habits and learn how to do the thing properly. Different tasks demand different skills, but the skill of humility is always the same.
To the extent that any earthly teacher is worthy of the name, it is only because they are first and foremost a student of the Reality being studied. Even Jesus is the Teacher only because he is the Student:
The Son can do nothing by himself; he can do only what he sees his Father doing, because whatever the Father does the Son also does. For the Father loves the Son and shows him all he does" (John 5:19-20).
Within the Trinity, the Son receives everything he is from the Father. (Indeed, the Father's identity consists entirely in his love, that is, in his breathing the Spirit into his Son. As Christians, we must not think that our Father is anything more or other than the Father of Jesus Christ, or that the Father held back anything of himself when he gave his Son.) The Son's divinity consists entirely of learning from the Father.
We also see this play out in the humility of his earthly life:
In the same way, Christ did not take on himself the glory of becoming a high priest. But God said to him,
“You are my Son;
today I have become your Father.” [Psalm 2:7]
And he says in another place,
“You are a priest forever,
in the order of Melchizedek.” [Psalm 110:4]
During the days of Jesus’ life on earth, he offered up prayers and petitions with fervent cries and tears to the one who could save him from death, and he was heard because of his reverent submission. Son though he was, he learned obedience from what he suffered and, once made perfect, he became the source of eternal salvation for all who obey him and was designated by God to be high priest in the order of Melchizedek. (Hebrews 5:5-10)
Now as our teacher, Jesus taught about the Kingdom of Heaven using stories taken from the crafts of his day. After instructing his disciples in the meaning of his parables, he says this:
“Have you understood all these things?” Jesus asked.
“Yes,” they replied.
He said to them, “Therefore every teacher of the law who has become a disciple in the kingdom of heaven is like the owner of a house who brings out of his storeroom new treasures as well as old.” (Matthew 13:51-52)
If Jesus is your teacher, he will also teach you about the Kingdom using your own craft, whatever it is. Not that your craft is God's Kingdom, but any time you have the bracing shock of really learning something, there is some way in which it is going to be similar to the Kingdom.
In college, I did some fencing. Recently I decided to take it up again, since this August. The game consists of trying to trick people into allowing themselves to be stabbed with a metal stick. But to explain how this connects onto spirtual topics, I need to go a little further back.
In high school I briefly took instruction from a karate instructor named Rob, for high school credit. (My mother and brother had much more extensive lessons though). Rob is a Christian, and he said that learning martial arts was very informative for his spirituality.
One learns about original sin—prior to being instructed, your instincts about what to do are pretty much always going to be wrong. Your stance is wrong, your posture is wrong, and your motions are wrong. The first thing you have to do is accept this as a fact, swallowing your wounded pride, and trust your teacher to correct you.
Then you have to actually do what the teacher says, without sliding back into what seems "natural"—until what is correct becomes second nature. (I'm pretty sure there's something about a second nature in the New Testament somewhere or other.) Rob also liked to say "practice doesn't make perfect, practicing perfect makes perfect".
Progress in holiness doesn't come about from "gradual improvement". Rather, it comes from being "perfect, just as your father in heaven is perfect" (Matthew 5:48). (By the way, in Greek the word "perfect" means complete, not flawless.) Of course, you can't do it. So the teacher comes alongside of you and moves you into the right shape. Jesus, the same personality who lived, died, and rose again, is there beside you showing you what to do. That's what we believe.
Then you become perfect—forgiving your enemies and loving the unlovable—for about five minutes, perhaps, before relapsing again. But at any time you can come back again.
The spiritual journey is more like continually being recalled back to what we ought to be, than like walking down a road to a destination. Getting into shape may take years, but getting into the right posture only takes seconds. In the same way, you can be who God wants you to be in a matter of seconds, if you really choose. Sanctification involves making that choice over and over again.
This may sound like hard work, but it isn't salvation by works. There's no nonsense about merit or deserving here. "It is not the healthy who need a doctor, but the sick" (Mark 2:17). And when corrected, you don't have to waste time agonizing about it. That's just pride. Just allow yourself to be corrected, and then think of the next thing.