One good quote for saying thank you is "Feeling gratitude and not expressing it is like wrapping a present and not giving it," by William Arthur Ward. Another example is "If the only prayer you ever say in your entire life is thank you, it will be enough," by Meister Eckhart. These quotes are suitable for use in thank you cards and other forms of messages.
Another quote from Ward that is suitable for saying thank you is "Gratitude can transform common days into thanksgivings, turn routine jobs into joy, and change ordinary opportunities into blessings." William Arthur Ward was an American writer in the 20th century and remains a highly quoted writer of inspirational material, as of 2015. Ward has had over 100 poems and articles featured in magazines such as Reader's Digest, The Christian Advocate and The Adult Student.
Born as Eckhart von Hochheim, Meister Eckhart was a German philosopher and mystic in the 13th and 14th centuries. He is recognized for his work with religious groups such as the Friends of God. Some of his most remembered works are his unusual sermons and his writings on metaphysics and spiritual psychology. He often strayed from the orthodox path, which led to him being accused of heresy and brought up before the local Franciscan-led Inquisition.