"Whoever believes in me does not believe in me only ..." (John 12:44)

"Whoever believes in me does not believe in me only, but in the One who sent me." (John 12:44)
With this clear statement by Jesus, how can some sectarian teachers teach that Jesus is the Supreme Being?

The fact is, Jesus is not the Supreme Being

He is very clear here, that he was sent by someone else. Does the Supreme Being get sent by someone else? Does the Supreme Being defer to someone else? Certainly not.

And Jesus is very clear that really believing in him means to believe in the Person who sent Jesus.

What does Jesus mean by "believe" here? "Believe" is being translated from the Greek word πιστεύω (pisteuō), which means "to think to be true, to be persuaded of, to credit, place confidence in" according to the lexicon. In other words, Jesus is speaking of trust here.

Jesus is speaking about someone trusting in what Jesus is teaching. Since Jesus was standing in front of the people he was speaking to, there was no question of his existence. Jesus is referring to them trusting in what he was teaching them.

So who is Jesus referring to here? 

Jesus has made this very obvious throughout his teachings. Consider these statements:
"Not everyone who says to me, 'Lord, Lord,' will enter the kingdom of heaven, but only he who does the will of my Father who is in heaven." (Matt. 7:21)
"For whoever does the will of my Father in heaven is my brother and sister and mother." (Matt. 12:50)
"Abba, Father, everything is possible for you. Take this cup from me. Yet not what I will, but what you will." (Mark 14:36)
Jesus has made it very clear that he is pleased not with the worship of himself, but with those who serve Jesus' "Father in heaven." Jesus is also clear that he wants to do God's will, not his own will.

So who is this One who sent me, this "Father in heaven," this "Abba" that Jesus is referring to?

The very first observation we can make from all of these verses is that Jesus is referring to a person other than himself. As he was denying his own will, and his own lordship in favor of God's will and God's Lordship, we can see that Jesus in no form or manner, considered himself the Supreme Being or represented himself as the Supreme Being.

Yet by referring to the Supreme Being as the "One who sent me," we can arrive at the conclusion that Jesus was representing God. To be sent by someone, and to be speaking on behalf of someone means to represent that person.

So Jesus was clearly God's representative.

But what about those ecclesiastical Christians who preach that we need to take Jesus into our hearts, and accept him as our savior? Are they wrong?

Jesus clarifies this as well, as he completes the statement made in Matt. 7:21 above:
"Not everyone who says to me, 'Lord, Lord,' will enter the kingdom of heaven, but only he who does the will of my Father who is in heaven. Many will say to me on that day, 'Lord, Lord, did we not prophesy in your name, and in your name drive out demons and perform many miracles?' Then I will tell them plainly, 'I never knew you. Away from me, you evildoers!'" (Matt. 7:22)
Isn't this what ecclesiastical sectarian teachers are doing - prophesizing or preaching in Jesus' name, driving out demons in Jesus' name, and (supposedly) performing miracles in Jesus' name?

Yet Jesus not only does not condone this. He tells them, "Away from me, you evildoers!" Why are they "evildoers"? Aren't they doing good things by preaching in Jesus' name, performing miracles (supposedly) and theoretically driving out demons in Jesus' name?

Jesus' criterion is simple: "but only he who does the will of my Father who is in heaven." Jesus is only pleased by us serving God. He wants our focus and attention to be on God. He wants us to do God's will, and see that Jesus' sole purpose was to do God's will. Note that only a person can have a will.

So who is this Person that Jesus is referring to, and why do so few sectarian teachers teach about Him?

Because they do not know Him.

And for those sectarian teachers who do refer to the Supreme Being, they perceive God as either an old guy with a long grey beard who sits up on a throne in the clouds, or as a vague and impersonal force. They think that because God is older, he must have wrinkled skin and grey hair. Or He has no shape or form. This is because, again, they do not know Him.

These are erroneous and speculative depictions of the Supreme Being. God is not subject to time. He is not subject to aging. These are elements of the physical world, and elements of the physical body. God created time, and he designed the aging process of the physical body. He is not subject to it.

And just because the Supreme Being lives outside the confines of time and space does not mean He has no form.

While the Supreme Being is present everywhere through His expansions, God has form, and personally dwells in the spiritual realm. This is indicated clearly by Jesus, as he referred to the Supreme Being numerous times as, "my Father who is in heaven."

God is the most beautiful being. 

He is attractive, radiant, gentle, caring and strong. He is also ever-youthful. God is not this aging old guy with grey hair depicted in so many renderings amongst churches and paintings. God is the most beautiful being in existence.

God is also the most intimate Friend and Relative to each of us. Prior to our self-centered downfall into these temporary physical bodies and this physical dimension, we were each intimately attached to the Supreme Being within the spiritual realm. And it is for this reason that most of us spend a significant portion of our lives looking for that special "soul-mate." We are, in fact, looking for the Supreme Being, our Dearmost Friend.

It is for this reason that Jesus doesn't want our worship on him. He wants us to worship the Supreme Being, give our entire lives to the Supreme Being, and love the Supreme Being. Why? Because he loves the Supreme Being and knows this and only this will make us happy. He knows that we will only be happy when we return to our natural position of loving, caring for and serving the Supreme Being. This is why his most important teaching was:
“‘Love the Lord your God with all your heart and with all your soul and with all your mind.' This is the first and greatest commandment." (Matt. 22:37-38)