The Holy Spirit

From the Small Catechism:

I believe that I cannot by my own reason or strength believe in Jesus Christ, my Lord, or come to Him; but the Holy Ghost has called me by the Gospel, enlightened me with His gifts, sanctified and kept me in the true faith; just as He calls, gathers, enlightens and sanctifies the whole Christian Church on earth and keeps it with Jesus Christ in the one rue faith.  In this Christian Church He daily and richly forgives me and all believers all our sins; and at the last day He will raise up me and all the dead, and will grant me and all believers in Christ eternal life.  This is most certainly true.