What did al-Ghazali say about gratitude (shukr)?

"Gratitude, too, has many levels, the highest of which we have discussed, and it encompasses lesser matters. For instance, a servant’s modesty due to Allah's continual gifts is gratitude. Recognizing one’s shortfall in gratitude is gratitude, apologizing for the lack of gratitude is gratitude, knowing the magnitude of Allah’s forbearance and concealment is gratitude, and acknowledging that blessings are from Allah without deserving them is gratitude."

"knowing the magnitude of Allah’s forbearance and concealment is gratitude, and acknowledging that blessings are from Allah without deserving them is gratitude. The knowledge that gratitude itself is a blessing from Allah and His gift is gratitude, as is humility toward blessings and acting humbly in them. Gratitude to intermediaries is gratitude, as the Prophet, peace be upon him, said, "Whoever does not thank people does not thank Allah."

"They are hindered by ignorance and heedlessness from recognizing blessings, and gratitude for blessings is inconceivable without recognizing them first. Even if they recognize a blessing, they think that gratitude for it is merely to say, "All praise belongs to Allah, all thanks belongs to Allah," with their tongues. They do not understand that the essence of gratitude is to use the blessing in completing the wisdom intended by it, which is obedience to Allah Almighty."

"Blessings can be divided into absolute blessings, which are entirely positive, and conditional blessings, which may have both positive and negative aspects. Absolute blessings in the Hereafter include a servant's happiness near Allah Almighty. In this world, they include faith, good character, and what supports them. Conditional blessings might include wealth, which can be used positively in religious matters but might also lead to corruption."

"The purification is proportional to the extent of one's giving and the joy in spending for the sake of Allah Almighty. The third meaning of zakat is gratitude for blessings. Allah Almighty has bestowed blessings upon His servants, both in themselves and in their wealth. Physical acts of worship show gratitude for bodily blessings, while financial acts of worship show gratitude for financial blessings."

"If these circumstances are equal for him, he should know that his motive is to establish the Sunnah of gratitude and discussion of blessings. Otherwise, he is deluded. When one knows their motive is the Sunnah of gratitude, they should not neglect fulfilling the donor's right. If the donor loves gratitude and publicity, it is better not to thank him openly, as supporting him in seeking gratitude is unjust. Seeking gratitude is unjust."

"God loves for His servant to witness His blessings, acknowledge them, praise Him for them, and love Him for them, not to be absent from them or from witnessing them. Gratitude is described as the bond of existing blessings and the hunt for lost blessings. The gratitude of the common people is for food, drink, clothing, and bodily sustenance, while the gratitude of the elite is for the oneness of God, faith, and the sustenance of the hearts."

"made Your angels prostrate before him, and taught him the names of all things. How did he thank You?" اللّٰه replied, "He knew that all of this was from Me, and his recognition of that was his gratitude to Me." Gratitude is also described as delighting in praising Him for gifts not earned. Al-Junayd, when asked about gratitude as a boy, replied, "Gratitude is not to use any of اللّٰه's blessings to commit sins." When asked where he learned this, he answered, "From sitting with you.""

"just as He is praised for His benevolence and justice, and gratitude is for benevolence and blessings. Thus, everything that gratitude pertains to, praise also pertains to, but not vice versa. Everything that praise pertains to, gratitude also pertains to, but not vice versa. Gratitude can be expressed through the limbs, while praise is expressed through the heart and tongue."

"Nothing is more harmful to a servant than his weariness of God's blessings; for then he does not see them as blessings, nor thank Him for them, nor rejoice in them — rather he resents them, complains of them, and counts them a calamity, and this while they are among God's greatest blessings upon him. Most people are enemies of the blessings God gives them and do not realise it: God opens His blessings to them, and they strive with all their effort to push them away and turn them back, out of ignorance and injustice."