Brethren and sisters, the Bible can be no more plainer than it is.  Our God is not the author of confusion, I Corinthians 14:33.  He knew how to communicate unto us His Word and that He did through the written Word of God, II Timothy 3:16-17.  God can be no clearer in what He has said about the need to teach others.  Friends, if we do not obey His Word, we will suffer eternal condemnation!
Matthew 7:13-14 says,

“Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat:  Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.”

Revelation 21:27 says,

“And there shall in no wise enter into it any thing that defileth, neither whatsoever worketh abomination, or maketh a lie: but they which are written in the Lamb’s book of life.”

This means that no sin can enter within the wonderful city of gold, called Heaven.  In that place, where God shall wipe all tears, in that place, where there is no more death, no more sadness, and no more pain, there can be no sin.
Romans 2:5-11 says,

“But after thy hardness and impenitent heart treasurest up unto thyself wrath against the day of wrath and revelation of the righteous judgment of God; Who will render to every man according to his deeds:  To them who by patient continuance in well doing seek for glory and honour and immortality, eternal life:  But unto them that are contentious, and do not obey the truth, but obey unrighteousness, indignation and wrath, Tribulation and anguish, upon every soul of man that doeth evil, of the Jew first, and also of the Gentile; But glory, honour, and peace, to every man that worketh good, to the Jew first, and also to the Gentile:  For there is no respect of persons with God.”

Matthew 25:46 says that those in sin shall go away into everlasting punishment, but the righteous into life eternal on the Judgment Day to come, a day when we know not, Matthew 24:44.
We ought to be crying forth in this world that each man and woman would do as Peter said do in Acts 2:40.  We ought to be saying as He did, to “Save yourselves from this untoward generation.”
There is no other way to be saved than by obeying the Gospel of Jesus Christ (Acts 4:12).  Hebrews 5:9 says about Jesus, “And being made perfect, he became the author of eternal salvation unto all them that obey him;”.   We ought to teach, because the world will be lost without the Gospel.
-Jason Gann, Online Instructor for Tennessee Bible College