This work seeks to analyze the thought of Newman contained in the Lectures on Justification. These lectures were written in 1838 and they present a Via Media between the Roman and Lutheran positions when studying the notion of justification. They present a summary of what justification by grace means. Newman presents the position of the Anglican Church with regard to justification highlighting that it is not only by faith nor only by works that believers are justified; rather, it is through the presence of the Holy Spirit in the soul that justification is made possible. The indwelling of the Spirit is the essence of justification. Newman develops a theology of justification that is in accordance with the classical and Catholic understanding of grace. God is the one who justifies; the human person collaborates with God’s action. The goal of Newman is to put the attention not so much on the subject but on the agent of justification, the Holy Spirit. By doing this he answers the two predominant positions, that of the Roman School and that of Lutherans.