1 John 3:2 Beloved, now are we the sons of God, and it doth not yet appear what we shall be: but we know that, when he shall appear, we shall be like him; for we shall see him as he is..

Who is writing this
John the Apostle is said to be the author of this Epistle and was probably written in Ephesus between the years 100-110AD.

Why is he writing it.
The Epistle was written to counter the heresies that was saying that Jesus did not come "in the flesh," but only as a spirit. It also defined how Christians are to discern true teachers: 
by their ethics, 
their proclamation of Jesus in the flesh, 
and by their love.  
Our text, 1 John 3:2 was to encourage and strengthen the believers.

Who is he writing it to.
John said "...now are we the sons of God..." who was he writing to? Who is the Beloved he is speaking to?
Children of God, the beloved. Those that were and are overcoming.

John in verse 1 reminds us of God's love for us.
1John 3:1 Behold, what manner of love the Father hath bestowed upon us, that we should be called the sons of God: therefore the world knoweth us not, because it knew him not. 

When it seems like the world hates us.... remember how the world treated Jesus.
No matter how bad the world may treat you, if you are a child of God, you have some great promises one of which is persecutions. ( 2 Tim. 3:12 )
We can learn from Paul as he contended with his thorn in the flesh ( 2 Cor. 12:7 - 8 ) . Yet God told Paul as He tells us today, His Grace is what we need. ( 2 Cor.12:9 ). That Grace strengthens us through tribulations and persecutions. ( 2 Cor. 12:10 )
I heard one preacher say once, "if you are not having troubles with the world, maybe you need to check your relationship with Jesus"
What is your relationship with Jesus?

1 John 5:1 Whosoever believeth that Jesus is the Christ is born of God: and every one that loveth him that begat loveth him also that is begotten of him. 
1 John 5:2 By this we know that we love the children of God, when we love God, and keep his commandments. 
1 John 5:3 For this is the love of God, that we keep his commandments: and his commandments are not grievous. 
1 John 5:4 For whatsoever is born of God overcometh the world: and this is the victory that overcometh the world, even our faith. 
1 John 5:5 Who is he that overcometh the world, but he that believeth that Jesus is the Son of God? 

What John is saying here is, because we believe in Jesus (entrusting our spiritual well being to Jesus Christ )  certain things happen in our hearts and minds:
We love the brethren
We keep His commandants.
We overcome the world.
We see the world differently and the world should see us differently.
I heard one preacher say once that when he got saved, his want to's changed.  ( 2 Cor 5:17 )
Our actions and behavior is not what saves us, but our actions and behavior should show we are saved.
We don't overcome the world to get saved, we get saved to overcome the world. ( 1 John 5:4 - 5 )
James says it this way.
James 2:18 But someone will say, "You have faith, and I have works." Show me your faith without your works, and I will show you my faith by my works.
James 2:19 You believe that there is one God. You do well. Even the demons believe --- and tremble!
James 2:20 But do you want to know, O foolish man, that faith without works is dead?

Okay we know we are children of God, what does 1 John 3:2 personally say to us?
It says we have a future, a fantastic future..
This body we have now, this life we have now, has limits. Its getting older, perhaps you notice you can no longer do things you use to be able to do, it gets sick, it has needs that has to be maintained, and we know that if Jesus tarries, we must die.( Heb. 9:27 )
This verse is telling Christians that we have a future body.  In this future body we will no longer suffer with pain and sorrow, no more worry about death, in fact God will wipe away our tears.(Rev 21:4 )
1 John 3:2 is telling us when, it says "....when He shall appear, we shall be like him; for we shall see him as he is...."
Oh glorious day.
We shall be like Him.
Today, we can not even imagine how glorious Jesus is.
Just what does it mean, ..."we shall be like Him..." the Greek word translated like is homoios
hom'-oy-os
From the base of G3674; similar (in appearance or character): - like, + manner.
Oh Glorious Day!
Picture Jesus, picture us.

Are you in that group of what John addresses as Beloved?
You can be.
You must be born again