What is the theme in Brand by Henrik Ibsen?

Willpower is a theme in the play. Depending on how one looks at the ambiguous ending of the play, Brand's iron strength of will is either a curse or a blessing. If one interprets the ending statement, "God is Love!" to mean that Brand should have focused less on prideful will and more on love, then it is a curse. If, however, one takes the voice to mean that God is acknowledging Brand's hard work and welcoming him to heaven at the hour of Brand's death, then his will is a blessing. In any case, Brand's will is his personal driving force, and it becomes the driving force of the play.