The Bible does not mention any specific gift given to Christians as a sign of power over unbelievers.
However, there are passages that refer to spiritual gifts given to believers for the purpose of building up the church and serving others, such as:
* 1 Corinthians 12:4-11: This passage discusses various spiritual gifts, such as wisdom, knowledge, faith, healing, miracles, prophecy, discernment, tongues, and interpretation of tongues, all empowered by the same Spirit.
* Romans 12:6-8: This passage lists gifts such as prophecy, service, teaching, exhortation, giving, leadership, and mercy.
* Ephesians 4:11-13: This passage mentions apostles, prophets, evangelists, pastors, and teachers, given to equip the saints for ministry and build up the body of Christ.
Additionally, some interpretations see miraculous events, such as healing, as signs of God's power and validation of the Christian message, which could have an impact on unbelievers.
It's important to note that these gifts are generally understood to be for the benefit of the church and to spread the Gospel, rather than to demonstrate power over those who do not believe.