We find here the description of a liar.  It is one who denies that Jesus is the Son of God, the Christ.  One who does not accept that Jesus came in the flesh is a liar and an anti-Christ and God is not in them.  But if they acknowledge that Christ is the Messiah, has both the Father and Son(1).

One must be careful when listening to odd, weird or other strange doctrines.  They could be a ploy of seducing spirits and devils(2)(3)...   and the results ofsaying 'God bless you' to them can bring negative consquenses(4).

The Believer must beware and take heed that they don't fall into the clutches of false doctrines(5)...    If we've heard the Word of God then are led astray we open ourselves to loss of contact with God(6).

When we are taught that which is truth, that which is proven by Scriptures that have come from the beginning of time, the scriptures called the Bible...  the Word of God(7).

Once we have been given the Word of truth, we must determine in our hearts that we will abide in it and allow it to live in us...

Remember, this is giving us a warning that we, the Believers, can be seduced by false doctrines(8).  When we are deeply rooted in Christ Jesus, grounded and established in the truth of the Word of the Living God...   We are instructed to be deeply thankful to the extreme for the truth, and what Christ has done for us(9).

When we are living in the depths of Christ, deeply loving Him, we will need no man to insist that their teaching is the only truth...   but the annointing of the Spirit of God will alert you to misunderstandings, uneducated teachings that man would like you to believe but when we study the Word(10)...   and the Spirit will show you the truth of God's Word(11).

Why did John give us these warnings of false doctrines?  Because he was well aware that we can be duped and led off by the doctrines of seducing spirits and devils(2)(3).  But why is this so important?  Because if we give in to the lies of false teachings, we will not have the confidence of being a Child of God and we'll have great shame when Christ comes for the Church.

When we come to the understanding that Christ is indeed the epitome of Righteousness, then it's our duty to stive to live in righteousness also(12)...   We are to to just as God...  living in His Character and imitating His ways(13)(14).  I love the slogan "What Would Jesus Do?"  When situations, no matter how small and insignificant they are, we should ask ourselves that question...   It would be ideal for us to get into the habit of asking that one question...
 

References:

A college graduate applied for a job at the Central Intelligence Agency.

Together with several other applicants, he was given a sealed envelope and told to take it to the fourth floor.

As soon as the young man was alone, he stepped into an empty hallway and opened the packet.

Inside, a message read:    "You're our kind of person.  Report to the fifth floor."