The theme of this book is Christian spirituality. It is part of the Concordia Theological Library series, which deals with Lutheran systematic theology. The themes of prayer and vocation are analyzed as a result of our justification in Christ and how we exercise our Christian vocation in our daily lives. There is nothing written in Spanish in the academic field on this topic. Theology students and pastors alike will be able to discover the connection between God's forgiveness and the new Christian way of life that He produces after our justification.