What did Jesus mean when he said, he must first bind the strong man, and than he can spoil his goods in. Matt 12:29 (KJV)?

He had to bind Satan before He could save those who were bound by Satan.

The Pharisees had accused Jesus of casting out devils by means of Beelzebub, the prince of devils. Jesus explained that Satan cannot cast out Satan. So if the power comes from God, then the kingdom of God is upon them. then he gives a simpler illustration about the strong man's house for their understanding

The NIV bible makes it easier to understand; "Or again, how can anyone enter a strong man’s house and carry off his possessions unless he first ties up the strong man? Then he can plunder his house."--Matthew 12:29 NIV (New International Version)

Let's give you an illustration :

The Watchtower holds the Jehovah's Witnesses in bondage, enslaved to itself. It is the strong man that prevents Jehovah's Witnesses from coming to the truth and knowing God for themselves.

So to deliver any J W it is first necessary to show or prove the falsity of the Watchtower. Once its hold over Jehovah's Witness is broken or bound then there is opportunity for them to be set free and come to know the truth and to know God for themselves.

So it is for all who are held by some false notion or lie. Break or bind that and they will have opportunity to be delivered.

In casting out demons it was necessary for Jesus to bind Satan who had power over them.

he didn't mean anything by it. jesus doesn't exist.

it's like asking "what did Voldemort mean when he met with the Death Eaters"

grow the fuc* up!!

I think it would be who is under satan, ruling this world, imprisoning all

contained here.

Claiming we are all his.

To rescue us, whoever rules under satan must be bound,

also...the rapture...Satan won't let us go.

But go we do.

Jesus is addressing the Pharisees assertion that he is casting out demons by the power of Beelzebul. He is saying hypothetically, that a person cannot carry off a strong man's possessions unless he bind the strong man up first. So he's alluding to the fact that he must overpower Satan to cast out Satan's demon, and that the Pharisees' assertion is foolish.

he's talking about atheists going to hell i think

If the strong are weak in faith they can feel threatened by the thoughts of others!

so Satan was still bound when Jerusalem was annihilated in 70 A.D.?

He was talking about casting out evil spirits ..