In the never ending discussion about whether or not Mormons are Christian (which, of course, they are) we routinely hear definitions of “Christian” that involve biblical meanings of “disiple”. It is a worthy task to try and determine exactly what is implied by the term “disciple” in this context.
John 8:31 (King James Version) 31Then said Jesus to those Jews which believed on him, If ye continue in my word, then are ye my disciples indeed;
What does this mean? Many critics would have us believe that “continue in my word” merely suggests that a disciple of Jesus must never stray from an unflawed understanding of religious truth. In other words, to “continue in my word” according to Johnny includes only those with a perfect understanding and belief in God’s metaphysical nature, in the complex mechanics of grace and salvation, of the eschatological events that Jesus foretold, and of an ability to accurately comprehend and believe in all other abstract principles of Jesus’ “word”.
But what are the consequences of such an interpretation? How many people, ever, have actually achieved this goal? Trinitarians agree that the complexities of the Godhead are beyond the comprehension of any mortal. The mechanics of the atonement are largely a mystery to all men, regardless of what outline you choose to place it in. How many individuals could confidently explain the events that will occur in the Millenium and beyond? The inevitable consequence is almost nobody “continue[s] in [Jesus’] word”, and thus almost nobody is a true Christian.
We need a better understanding of John 8:31, preferably one that doesn’t exclude the vast majority of people who have ever thought they were Christians.
I suggest we interpret Christ’s message in John 8:31 in light of similar statements He made elsewhere.
“This is my Father’s glory, that you may bear fruit in plenty and so be my disciples” (John 15:8, New English Bible).
“By this shall all men know that ye are my disciples, if ye have love one to another. John 13:35
Both of these statements by Christ involve questions of ethics, behavior, and lifestyles. They say next to nothing about doctrinal affirmations. Doesn’t it make sense to interpret John 8:31 in light of these similar passages?
I propose that “continue in my word” should be understood in light of who Jesus was talking to. John gives us a hint:
John 8:31 (King James Version) 31Then said Jesus to those Jews which believed on him, If ye continue in my word, then are ye my disciples indeed;
I propose that “continue in my word” should be interpreted as “believe on him”.
Believing on Jesus Christ is much more meaningful accomplishment than comprehending and believing every nuance of the complex creeds and catechisms formulated by the various churches.
Believing on Jesus Christ is simple. It is to do one’s best to follow him. It does NOT mean to perfectly follow him. It just means to believe on him.
Let’s take this one step further.
What exact aspect of Christ’s “word” were they believing on? John 8:21-31 reads:
21Then said Jesus again unto them, I go my way, and ye shall seek me, and shall die in your sins: whither I go, ye cannot come.
22Then said the Jews, Will he kill himself? because he saith, Whither I go, ye cannot come.
23And he said unto them, Ye are from beneath; I am from above: ye are of this world; I am not of this world.
24I said therefore unto you, that ye shall die in your sins: for if ye believe not that I am he, ye shall die in your sins.
25Then said they unto him, Who art thou? And Jesus saith unto them, Even the same that I said unto you from the beginning.
26I have many things to say and to judge of you: but he that sent me is true; and I speak to the world those things which I have heard of him.
27They understood not that he spake to them of the Father.
28Then said Jesus unto them, When ye have lifted up the Son of man, then shall ye know that I am he, and that I do nothing of myself; but as my Father hath taught me, I speak these things.
29And he that sent me is with me: the Father hath not left me alone; for I do always those things that please him.
30As he spake these words, many believed on him.
31Then said Jesus to those Jews which believed on him, If ye continue in my word, then are ye my disciples indeed;
It appears that what the believing Jews had just been taught, and had believed, was an ambiguous sermon about his relationship to his Father (who they didn’t realize was God) and Christ’s determination to do the will of his Father (again, that they didn’t realize was God).
Not much detailed doctrine there. It seems that they simply believed that Christ was something special, was what he claimed he was, even if they didn’t fully understand what that was.
Lehi's Library 
Interesting take on the “Are Mormons Christian?” argument.
The term “disciple” (found 232 times in the Gospels and Acts) is derived from the New Testament Greek, and comes into the English language by way of the Latin “discipulus,” meaning “a learner”.
According to this definition, I am a disciple of Jesus because I study the scriptures and learn from Jesus’ words and example. As an attorney, I am also a disciple of the law, and my children could be termed as my disciples as they learn from me.