The Bible and Lutherans teach that the Holy Spirit causes the heart to trust in Jesus as its Savior. The Holy Spirit creates and maintains faith by means of the gospel in God's Word and the sacraments of Holy Baptism and Holy Communion. We believe, therefore, that our conversion is not our work. It is entirely the work of God's grace. Rejection of the gospel is, however, entirely our own fault.
1 Corinthians 6:11
You were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and by the Spirit of our God.
John 17:17
Sanctify them by the truth; your word is truth.
2 Thessalonians 2:13,14
From the beginning God chose you to be saved through the sanctifying work of the Spirit and through belief in the truth. He called you to this through our gospel, that you might share in the glory of our Lord Jesus Christ.
Romans 10:17
Faith comes from hearing the message, and the message is heard through the word of Christ.
Acts 2:38
Peter replied "Repent and be baptized, everyone of you, in the name of Jesus Christ so that your sins may be forgiven. And you will receive the gift of the Holy Spirit."
Acts 15:3
They told how the Gentiles had been converted.
Acts 7:51
You stiff-necked people... You always resist the Holy Spirit.