Let us consider an abstract group with the following presentation <IMG SRC="/fbpe/img/proy/v21n1/for04.jpg" WIDTH=499 HEIGHT=60> <IMG SRC="/fbpe/img/proy/v21n1/for05.jpg" WIDTH=358 HEIGHT=40>. We provide conditions in order to find a faithful, discrete and geometrically finite representation <IMG SRC="/fbpe/img/proy/v21n1/for06.jpg" WIDTH=315 HEIGHT=29>that is, to represent G as a group of isometries of the hyperbolic three space H 3