How do we know that Jesus has the power to cast out demons?

Luke 11:20 states that Jesus casts out demons by the 'finger of God,' which in the Gospel of Matthew is identified as the Spirit of God. This indicates that the power of the Holy Spirit is the means by which Jesus performs these acts of deliverance. The effectiveness and finality of His work are underscored by the fact that those who are delivered by Him remain secure in their liberation. Unlike those who may experience temporary relief, Jesus ensures that His followers are eternally safeguarded. This is foundational to understanding His ministry and the power He wields against the forces of evil.