Did you ever notice there are bad things that tend to "run in the family". When we accept that things like cancer, diabetes, hereditary traits like anger, violence and others are all caused by demons, then we can begin to address the problem. please see our upcoming article can Christians have demons for further explanation over how they are there. These demons came in in what we call a generational curse line. They come from the sins of our fathers or ancestors.
Keeping mercy for thousands, forgiving iniquity and transgression and sin, and that will by no means clear the guilty; visiting the iniquity of the fathers upon the children, and upon the children's children, unto the third and to the fourth generation. Exodus 34:7
The LORD is longsuffering, and of great mercy, forgiving iniquity and transgression, and by no means clearing the guilty, visiting the iniquity of the fathers upon the children unto the third and fourth generation. Numbers 14:18
So how is this different now? Today we are under the New Covenant. This means Jesus has given us authority over the demons that come in through this iniquity. Now they can be cast out by that authority and the sons don't have to accept the sins of their fathers (or daughters and mothers). Just like with our salvation though we must ask.
In those days they shall say no more, The fathers have eaten a sour grape, and the children's teeth are set on edge. But every one shall die for his own iniquity: every man that eateth the sour grape, his teeth shall be set on edge. Behold, the days come, saith the Lord, that I will make a new covenant with the house of Israel, and with the house of Judah: Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the Lord: But this shall be the covenant that I will make with the house of Israel; After those days, saith the Lord, I will put my law in their inward parts, and write it in their hearts; and will be their God, and they shall be my people. And they shall teach no more every man his neighbour, and every man his brother, saying, Know the Lord: for they shall all know me, from the least of them unto the greatest of them, saith the Lord: for I will forgive their iniquity, and I will remember their sin no more. Jeremiah 31:29-34
And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues; Mark 16:17
And to have power to heal sicknesses, and to cast out devils: Mark 3:15
Behold, I give unto you power to tread on serpents and scorpions, and over all the power of the enemy: and nothing shall by any means hurt you. Luke 10:19
And he healed many that were sick of divers diseases, and cast out many devils; and suffered not the devils to speak, because they knew him. Mark 1:34
But if I cast out devils by the Spirit of God, then the kingdom of God is come unto you. Matthew 12:28
All these verses show our authority, that diseases are caused by demons, and how they relate to generational sin or iniquity. There are more if you choose to study the Bible. With this we should know how to break this generational curse through the New Covenant and blood of Jesus. As you can see we cast out demons by the Holy Spirit. It is the Holy Spirit that instructs on each case because each case is different therefore there is no simple formula to the task in the Bible.
We do know in order for sins to be forgiven we must go to the Father in prayer, whether it be ours or our ancestors. Here is a prayer to break generational curse lines so the demons can be cast out and not return.
I come to You now humbled at your feet. Lord I know that my fathers and ancestors have sinned and it has left doors open in my life. I am here to ask You to shut those doors. Lord I confess the sins of my fathers now:___________(insert what sins you know here) and any other that I am not aware of but You know what they are. I confess the sins back 20 generations and ask you to take them off me and my family. Let these be broken here and now with me. Lord I ask now that any curses, spells, witchcraft of any kind, and iniquity be cancelled and broken now. I ask that all cords be severed by angels now. Break any link to the sins of my fathers and any generational curses over me now. Lord I thank You and praise Your Holy Name. In Jesus name Amen.
Say this to address the issue with generational curse lines. May God bless you and Jesus keep you.