It takes might to fight. Deciding what the Torah tells us to do in a given situation is a battle of minds. In the end it's a win-win fight.
"And so does it say in the book of the wars of God 'love in the end.'" The Torah is "the book of the wars of God." It ends with love.
Father and son, mentor and disciple battle while engaged in the in-depth study of Torah. No matter who comes out right – love in the end.
In every unification of souls a certain degree of conflict must precede resolution. Solomon concludes his 28 times with war and then peace.
There is a special sense of pleasure in war, in victory. The pleasure of learning Torah should suffice to fill this psychological need.
Amongst all nations on earth physical war will cease when all come to engage in the study of Torah and experience its intrinsic delights.