In this article we analyze the expression „baptized in the Name of the Father and of the Son and of the Holy Spirit” (Mt. 28, 19b). Firstly, we mention the critics that challenge its matthaean origin (among which we enumerate the two quotation methods of Eusebius of Caesarea), and then we continue with the theologians who believe the text as being inspired; in the second chapter, starting from the meaning of the prepositions l.and B., and as well of the word eivj to. o;noma, we trace the main features of the phrase „to baptize in the name of...”; then there is a brief description of the presumed historical development„monadic, dyadic, triadic formula”; in the penultimate chapter we quote the liturgical sources of the first three centuries that contain the text Mt. 28, 19b; we end with the theology of the analyzed expression.