Hello Bringintruth,
Really nice meeting you here. Can I just say that I think you're blowing this out of all proportion. These muppets have no special powers except for their victims' superstition. They dance naked round bonfires uttering gibberish curses with their fingers crossed hoping that their victims are taken in and believe this tosh, and then scared witless, they fulfil these curses by accidentally falling downstairs or dropping a hot coffee in their lap, so they can claim that the curse has been fulfilled. It's all bovine pooh!!!
Yes. the Bible tells us we do have a battle against principalities and powers Ephesians 6:12 and if you were ever to meet Satan you may well have a short panic attack but no, Satan himself realises his battle with God is a battle for his survival, and he's lost that battle already. One day as spectators we will be there cheering on his final demise Revelation 20:10. Meanwhile you as a child of God are protected by Him, you may have little concept of the battle that's going on around you but in the same way God has any threat against you already covered 2 Kings 6:16-17.
So please ignore as best you can these stupid superstitious numpties and as the say in Liverpool, tell 'em to do one! If they continue to make a nuisance of themselves I'm sure there's anti-stalking laws in the US so just let the authorities deal with them. Please do not allow these people to make your life a misery and if they do approach you just let them know that God loves them and sent His son Jesus to die on the cross so they can be redeemed and taste for themselves the sweetness of His victory.
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Dear Lord God, I pray for my dear sister and ask that you will draw close to her with your comforting Holy Spirit. Give her the confidence to know and appreciate that the battle is yours and that your power is somewhat greater than immense. Confidence is what she lacks, so please dear Lord, lots of your blessings in that department. I pray she will instead focus upon you her God and Jesus her saviour, praising and worshipping you, relaxing in your love, quietly confident that nobody but nobody can snatch her from you.
Amen.