Q. Is it possible for someone not to obtain salvation because of demons? If one asks the Lord to save them, and they have demons or are oppressed by demons, could they not recieve salvation?
A. In 2 Cor 4:4 Paul wrote: “The god of this age has blinded the minds of unbelievers, so that they cannot see the light of the gospel that displays the glory of Christ, who is the image of God.”
This tells us that the enemy will try to prevent unbelievers from receiving the gospel message. But in Matthew 7:7-8 Jesus promised that everyone who asks will receive, everyone who seeks will find, and to everyone who knocks the door will be opened. Paul confirmed this in Romans 10:13 when he said that everyone who calls on the name of the Lord will be saved.
Therefore, it seems to me that even a person who is being demonically oppressed can exert his or her own free will, ask to be saved, and receive it.