The problem of reaching personal sanctity through Church, highlighted by the constitution Lumen Gentium issued by the Second Vatican Council, is one of key topics discussed in the theological works of the outstanding researcher Professor Father Wincenty Granat. He elaborated widely on the concept of Christian sanctity, which he identified with perfection. Drawing upon the texts of the Old and the New Testament, Father Granat emphasised that love is the foundation of sanctity. This is why, Father Granat taught about sanctity as friendship with Christ. Christ is an example of sanctity for all, this is why we all should follow Him. Servant of God Father Granat claimed strongly that the Church has its inner powers to transform sinners into saints, even though its full sanctity will come with eschatological times.