Morning star is another word for the devil and so is Samuel. He's not looking to God when he references "la estrella de la manana." This song is either about Mary Magdalen being angry about Jesus dying and leaving her so she basically curses God. Or this song could be about a person who has had a bad life and feels as if God has turned against him. Hence the reason he says "Cargo una navaja Dios mio parati. Cuantas veces me mordiste, and cuantas veces yo me fui." He is saying how many times God has cursed him and how many times he has left the light of God and his faith behind.