How do we know Christ's sacrifice applied to us?

We know that Christ's sacrifice applies to us through the work of the Holy Spirit who convicts us of our sin and leads us to faith in Christ. As stated in 1 John 4:15, whoever confesses that Jesus is the Son of God, God dwells in him and he in God. This mutual indwelling indicates that those who truly confess Christ are assured of His sacrifice on their behalf. Moreover, the spirit of adoption replaces fear with confidence (Romans 8:15), providing believers with the assurance that they are reconciled and secure in Christ. Thus, true faith accompanies the believer's recognition of Christ’s finished work.