In his commentary on Matthew Professor Douglas Hare writes: In an age when the word 'love' is greatly abused, it is important to remember that the primary component of biblical love is not affection but commitment. Warm feelings of gratitude may fill our consciousness as we consider all that God has done for us, but it is not warm feelings that Deut. 6:5 demands of us but rather stubborn, unwavering commitment. Similarly, to love our neighbor, including our enemies, does not mean that we must feel affection for them. To love the neighbor is to imitate God by taking their needs seriously.
Exegetical Notes, from Matthew, Interpretation Commentaries, by Brian Stoffregen