The article presents the issue of Christian brotherhood. The theological understanding of brotherhood has been shown as the communion with God and having its source in the act of creation. Man created in the image and likeness of God participates in the communion with God, as well as in the communion of people. In the latter communion an important role is played by psychological processes, including the conditions of interpersonal communication. The last part of the article presents a mature interpersonal communication as a crucial condition of creating communion and mutual brotherhood.