Sourced

• Whoever does not express his gratitude to people will never be grateful to God.
  • The Prophet Muhammad, reported in al-Tirmidhī, al-Ţabarānī, Musnad Ahmad, Musnad Abū Hanīfah, Musnad Abu Ya'la.

• We can set our deeds to the music of a grateful heart, and seek to round our lives into a hymn — the melody of which will be recognized by all who come in contact with us, and the power of which shall not be evanescent, like the voice of the singer, but perenninal, like the music of the spheres.
  • William Mackergo Taylor, reported in Josiah Hotchkiss Gilbert, Dictionary of Burning Words of Brilliant Writers (1895), p. 290.

• Thankfulness is the tune of angels.
  • Edmund Spenser, reported in Josiah Hotchkiss Gilbert, Dictionary of Burning Words of Brilliant Writers (1895), p. 290.

• Did you ever think of the reason why the Psalms of David have come, like winged angels, down across all the realms and ages,— why they make the key-note of grateful piety in every Christian's soul, wherever he lives? Why? Because they are so full of gratitude. " Oh, that men would praise the Lord for His goodness and for His wonderful works to the children of men!"
  • Alphonso Albert Willits, reported in Josiah Hotchkiss Gilbert, Dictionary of Burning Words of Brilliant Writers (1895), p. 290.

• Do not let the empty cup be your first teacher of the blessings you had when it was full. Do not let a hard place here and there in the bed destroy your rest. Seek, as a plain duty, to cultivate a buoyant, joyous sense of the crowded kindnesses of God in your daily life.
  • Alexander Maclaren, reported in Josiah Hotchkiss Gilbert, Dictionary of Burning Words of Brilliant Writers (1895), p. 290.

Unsourced

• Express your appreciation, sincerely and without the expectation of anything in return. Truly appreciate those around you, and you'll soon find many others around you. Truly appreciate life, and you'll find that you have more of it.
  • Ralph Marston

• Gratitude is a virtue disposing the mind to an inward sense and an outward acknowledgment of a benefit received, together with a readiness to return the same, or the like, as occasions of the doer of it shall require, and the abilities of the receiver extend to.
  • Anonymous

• He who receives a good turn, should never forget it: he who does one, should never remember it.
  • Pierre Charron

• O Lord, that lends me life, lend me a heart replete with thankfulness.
  • William Shakespeare

• What causes such a miscalculation in the amount of gratitude which men expect for the favors they have done, is, that the pride of the giver and that of the receiver can never agree as to the value of the benefit.
  • François de La Rochefoucauld

• If gratitude is due from children to their earthly parents, how much more is the gratitude of the great family of man due to our Father in heaven!
  • Hosea Ballou