An issue that causes much discussion nowadays in biblical exegesis is the status of the scroll of the so-called Twelve Minor Prophets. Scholars are divided among those who understand that the Twelve should be considered as a unified literary work and those who understand that the writings that are part of that scroll should be seen as independent in relation to the others. This thesis, looking at offering a contribution to the discussion of the matter of the Twelve, has its starting point in a presentation of the status quaestionis of the research of the Twelve, and, going through a study of the text of the Book of Malachi and its organization, leads to the analysis of the last pericope of that writing, Ml 3.13-21, seeking for verifying its relations to the other texts of the whole of the Twelve, in general, and of the Book of Malachi, in particular. Special attention is given to the comparison between the text of Ml 3.13-21 and the Book of Joel, specially concerning the use that both texts make of the motif of the day of YHWH. This work comes to the conclusion that the pericope studied reveals stronger contacts with the rest of the Book of Malachi than with other texts of the whole of the Twelve, something that speaks in favour of the consideration of the last component of the Twelve as an independent writing.