As for thankfulness [shukr], the basic guidance on the subject is contained in the words of Allah (Almighty and Glorious is He) :
If you are thankful, I will surely give you more; but if you are ungrateful, My punishment is terrible indeed. (14:7)
This is reinforced by the traditional report, transmitted on the authority of 'Ata' (may Allah the Exalted bestow His mercy upon him), who said:
"I entered the presence of [the Prophet's widow] 'A'isha (may Allah be well pleased with her), and said: 'Tell us about the most amazing experience you ever had in the company of Allah's Messenger (Allah bless him and give him peace).' She wept at first, but then she said: 'Was there anything at all about him that was not a marvelous wonder? He came to me one night, and snuggled up beside me in my bed [firashi] until his skin was touching my skin. But then he said: 'O daughter of Abu Bakr, let me go, so that I may devote myself to the worship of my Lord.'
"She said: 'So I told him: "I love your nearness, but I prefer to respect your dearest wish." I therefore allowed him (Allah bless him and give him peace) to take his leave of me. So he got up, found a skin container full of water, and performed his ritual ablution [tawadda'a], pouring a considerable amount of water in the process. Then he stood erect, and started to perform the ritual prayer [qama fa-salla]. He wept as he did so, until his tears were streaming down onto his chest. Then he adopted the bowing posture [raka'a], and shed more tears. Then he prostrated himself [sajada], and again he wept. Then he raised his head, and wept still more. He went on like this (Allah bless him and give him peace) until Bilal (may Allah be well pleased with him) arrived on the scene, and so he told him about the ritual prayer [salat].
"'I then said: "O Messenger of Allah, what causes you to weep, when Allah has forgiven you your earlier and later sins?" To this he replied (Allah bless him and give him peace) :
"'"Should I not be a thankful servant ['abd shakur]? Why should I not do it, since Allah (Almighty and Glorious is He) has sent down to me the words of revelation:
Surely in the creation of the heavens and the earth, and the alternation of night and day, and the ship that runs upon the sea with that which is of use to human beings, and the water which Allah sends down from the sky, thereby reviving the earth after its death, and dispersing all kinds of beasts therein, and the distribution of the winds, and the clouds set in orderly array between heaven and earth--surely there are signs for people who can understand. (2:164) "'"
According to those who specialize in ascertaining the actual facts [ahl at-tahqiq], the true nature of thankfulness [haqiqat ash-shukr] is the acknowledgment of the benefaction of the benefactor [ni'mat al-mun'im], with an attitude of humility. In accordance with this meaning, Allah (Exalted is He) has described Himself as being the Most Thankful One [ash-Shakur] in the widest sense, that is to say, in the sense that He rewards His servants for their thankfulness. For the recompense of thankfulness [jaza' ash-shukr] is also called thankfulness [shukr], just as Allah (Almighty and Glorious is He) has said:
And the recompense of an evil is an evil just like it. (42:40)
It has also been said that the true nature of thankfulness [haqiqat ash-shukr] is the act of praising the beneficent person [muhsin] by mentioning his beneficence [ihsan]. The servant's thankfulness [shukr] to Allah (Exalted is He) is therefore expressed through the praise he offers to Him, by mentioning His beneficence [ihsan] toward His servant. As for the thankfulness [shukr] of the Lord of Truth (Glory be to Him) toward His servant, it is expressed through the praise He confers upon him, by making it known that he has acted beneficently for His sake. Furthermore, the beneficence [ihsan] of the servant represents his worshipful obedience to Allah, while the beneficence [ihsan] of the Lord of Truth (Glory beto Him) represents His bestowal of gracious favor [in'am] upon His servant. When the thankfulness [shukr] of the servant is genuine, it is not only a matter of utterance by the tongue, but also the heart's acknowledgment of the Lord's bestowal of gracious favor [in'am ar-Rabb].
Moreover, thankfulness [shukr] can be subdivided into several categories, namely:
1. Thankfulness expressed by the tongue [shukr bi'l-lisan]. This constitutes the acknowledgment of the benefaction [ni'ma] with an attitude of humble acceptance [istikana].
2. Thankfulness expressed by the body and the limbs [shukr bi'l-badan wa 'l-arkan]. This is the characteristic indication of loyalty and readiness to serve [al-wafa' wa 'l-khidma].
3. Thankfulness expressed by the inner feeling [shukr bi'l-qalb]. This requires a careful balance between the visible display of appreciation and the constant preservation of a sense of reverence.
It has also been said that thankfulness of the eyes [shukr al-'ainain] means that you overlook any fault you notice in your companion, while thankfulness of the ears [shukr al-udhunain] means that you ignore any fault you hear him accused of possessing.
In the simplest terms, thankfulness [shukr] means that you do not disobey Allah (Exalted is He) by misusing His gracious favors.
Here is another saying that clearly deserves to be quoted:
"Thankfulness [shukr] may mean the thankfulness of the learned scholars [shukr al-'alimin], in which case it will be among the subjects they discuss.
"Thankfulness [shukr] may mean the thankfulness of the dedicated worshippers [shukr al-'abidin], in which case it will be a feature of their actions.
"Thankfulness [shukr] may mean the thankfulness of those who know by direct intuition [shukr al-'arifin], in which case it will be expressed through their honest devotion to Him (Almighty and Glorious is He) in all their states and conditions. It will be expressed through their firm conviction that whatever is good in their experience, and whatever is manifested from them in the way of worshipful obedience, servitude, and remembrance of Him (Almighty and Glorious is He), is entirely due to His enabling guidance [tawfiq], His gracious favor, His help, His power and His strength (Almighty and Glorious is He). It will be expressed through their detachment from all of that, and their total absorption [fana'] in Him. It will be expressed through their acknowledgment of their own inability, deficiency and ignorance, and then through their humble submission to Him (Almighty and Glorious is He) in all conditions and circumstances."
It was Abu Bakr al-Warraq (may Allah the Exalted bestow His mercy upon him) who said:
"Thankfulness for a gracious favor [shukr an-ni'ma] means feasting one's eyes on the gift received, while preserving a sense of reverence."
As someone else once put it:
"Thankfulness for a gracious favor [shukr an-ni'ma] means that you regard yourself as no more deserving of it than a parasite [tufaili]."
It was Abu 'Uthman [al-Hiri] (may Allah the Exalted bestow His mercy upon him) who said:
"Thankfulness [shukr] is the conscious awareness [ma'rifa] of the fact that you are quite incapable of thankfulness."
Let us also consider the following wise sayings:
"Thankfulness for thankfulness [ash-shukr 'ala 'sh-shukr] is more complete than simple thankfulness [shukr]. This means that you regard your thankfulness as the result of His enablement [tawfiq], and you have received that enablement on account of the gracious favors bestowed upon you, so you give thanks to Him for the thankfulness He has enabled you to experience. Then you thank Him for the thankfulness-upon-thankfulness [shukr ash-shukr], and so on ad infinitum."
"Thankfulness [shukr] is the attribution of blessings to their Master [Mawla], with an attitude of humble submission to Him."
It was al-Junaid (may Allah the Exalted bestow His mercy upon him) who said:
"Thankfulness [shukr] means that you do not look upon yourself as worthy of the gracious favor you have received."
In several wise sayings, the meaning of the simple adjective shakir [thankful; grateful] is contrasted with the significance of the intensive form shakur [very thankful; most grateful; extremely appreciative]. For instance:
"The person who is simply thankful [shakir] is someone who gives thanks for what is available [mawjud], while the person who is very thankful [shakur] is someone who gives thanks for what is unavailable [mafqud]."
"The person who is simply thankful [shakir] is someone who gives thanks for the provision of benefit [naf'], while the person who is very thankful [shakur] is someone who gives thanks for the withholding of benefit [man']."
"The person who is simply thankful [shakir] is someone who gives thanks for the granting of gifts ['ata'], while the person who is very thankful [shakur] is someone who gives thanks for trial and tribulation [bala']."
"The person who is simply thankful [shakir] is someone who gives thanks in response to immediate delivery [badhl], while the person who is very thankful [shakur] is someone who gives thanks when delivery is subject to deferment [matl]."
