"[S]ervice is the principal way of showing gratitude to the Savior. We need to fill ourselves up with gratitude for His redeeming love, His infinite atoning sacrifice, His obedience to the will of the Father. As we become full of gratitude, it overflows into service, and “inasmuch as [we] have done it unto one of the least of these [his] brethren, [we] have done it unto [Him].” (Matt. 25:40.)
I love that. We can show gratitude to so many in so many ways. And one would think that being obedient was a way to show gratitude. But it isn't so much. Obedience reflects our desire and efforts to return to our Heavenly Father. But service goes beyond that. Service is a reflection of our gratitude. "Because I have been given much, I too must give" is the perfect hymn to illustrate that.