The article offers an interpretation of St. Paul’s thoughts regarding human’s reaching of the Christian ideal of humanity basing on Eph 4:17–5:2. The exegetical analysis of the selected passage is based on commentaries by writers of various Christian denominations, which makes this publication useful in the ecumenical field. In the article the reader can find numerous admonitions of the Apostle Paul concerning non-Christian life, and at the same time practical guidelines on the way of Christian life. In the analyzed passage Eph 4:17–5:2 the reader can see the consequences of adopting the new model of life indicated by the author of the letter to the Ephesians. These are the difficulties a person must overcome in order to live a pattern of life consistent with the gospel of Christ. This life should be filled with love, which becomes the conclusion of St. Paul’s words to the Ephesians as well as the conclusion of this publication.