Show Gratitude To Allah

52 Even then, We did forgive you; there was a chance for you to be grateful. (Al-Baqarah)
Gratitude to Allah is in doing your best to practice what pleases Him and in staying away from what He prohibits.
Another meaning of gratitude is that you should not use the favours that Allah has bestowed on you to disobey Him, like the wealth He gave you, the joints on your body, eyes, hands, sexual organs, etc.

Gratitude also means recognising the Bestower of favours and realising that however much you may thank Him, you will fall short of giving enough thanks to Allah.

18. And if ye would count the favour of Allah ye cannot reckon it. Lo! Allah is indeed Forgiving, Merciful. (An-Nahl)
They also said that gratitude is to show that you are thankful by your actions. There is a difference between Hamd (thanks) and Shukr (gratitude).

Hamd is by using your tongue, but gratitude is by your joints and actions. If Allah gives you good health, showing your appreciation for that will be by worship in all its ramifications.

For a rich man to show gratitude to Allah, he has to give Sadaqah to those who are poor.
It was reported that when Allah said to the household of David:

13. They made for him what he willed: synagogues and statues, basins like wells and boilers built into the ground. Give thanks, O House of David! Few of My bondmen are thankful. (Saba’)

David said, ‘O Allah! How do I show gratitude to You when gratitude itself is a favour from You?’
Allah said, ‘Yes, by recognising this, you know Me.’

David said, ‘O Allah! Show me the most hidden of Your favours on me.’
Allah said, ‘O David, ‘Breathe.’And David breathed.

Allah said, ‘O David! Who can fathom the extent of this favour?’
Still On The Children Of Israel
Two weeks ago, we discussed Musa and the Children of Israel. He left them to answer Allah’s summons to give him the Torah. But in his absence, some of them took the calf for worship. Harun tried to stop them from doing so in vain. So, he and the remaining people who did not participate in the false worship stayed away

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53 And remember, We gave Moses the Scripture and the Criterion (Between right and wrong): There was a chance for you to be guided aright. (Al-Baqarah)
The Torah here is referred to as both the Scripture and the Criterion; it means the same thing. The Book was given as a guide to the Children of Israel.

Repentance
54 And remember Moses said to his people: “O my people! Ye have indeed wronged yourselves by your worship of the calf: So turn (in repentance) to your Maker, and slay yourselves (the wrong-doers); that will be better for you in the sight of your Maker.” Then He turned towards you (in forgiveness): For He is Oft-Returning, Most Merciful. (Al-Baqarah)

He was addressing those among his people who took the calf for worship in his absence. You have indeed wronged yourselves by your worship of the calf. When you sin, you do not harm Allah but yourself. So, Musa called on them to repent to Allah for their actions.

Repentance is to revert to Allah penitent, regretting what has happened, confessing it was wrong and sincere, inward determination not to repeat the same act. One should seek Allah’s forgiveness and make amends if what he did involves the rights of others.
“…and slay yourselves (the wrong-doers);…”

How were they to kill themselves?
Killing themselves means controlling their souls in avoiding what Allah prohibits, doing what He commands and not exceeding the limits He imposes.

Another meaning is that those who did not worship the calf should kill those who did. It is said that they were made to stay in two straight lines, each facing the other: those who worshipped the calf on one row and those who did not on the other. Some scholars said that dark clouds covered them, and they kept killing themselves until Musa fell prostrate to Allah and cried, ‘O Allah! Children of Israel are perished.’ So, Allah lifted the dark clouds and declared that those who died were martyrs, and all the living were forgiven.

This killing, according to the most authentic position, did not differentiate between the 70 chosen people with whom Musa went to speak to his Lord and those who were convinced by Harun’s admonitions, who refrained from idolatry and those who worshipped the calf. The killing encompassed all.

Why were they ordered to kill themselves?
They were told to kill themselves because those who did not take part in the worship of the calf did not prevent those who did. One who can stop the commission of evil but refuses is equally guilty of the same act.
Hudhaifah (May Allah be pleased with him) reported: The Prophet (ﷺ) said, “By Him in Whose Hand my life is, you either enjoin good and forbid evil, or Allah will certainly soon send His punishment to you. Then you will make supplication, and it will not be accepted”. [At-Tirmidhi, who categorised it as Hadith Hasan].

Riyad as-Salihin 193
If Allah’s punishment arrives, it affects both the good and the bad – the bad because they are guilty, and the good for their silence when the act was committed.

The Children of Israel were ordered to kill themselves as punishment for the worship of the calf. Those who died were martyrs; the survivors were forgiven.

54 And remember Moses said to his people: “O my people! Ye have indeed wronged yourselves by your worship of the calf: So turn (in repentance) to your Maker, and slay yourselves (the wrong-doers); that will be better for you in the sight of your Maker.” Then He turned towards you (in forgiveness): For He is Oft-Returning, Most Merciful. (Al-Baqarah)

Allah’s Favour On Us
Let us now ponder over the mercy of Allah on the Ummah of Muhammad, sallallaahu alayhi wa sallam. Now, many times do we sin in a day or at night? Allah has not made things difficult for us as He did with the Children of Israel. He did not tell us to kill ourselves.

We are only to repent, and He will forgive us. During their time, when they sinned at night, in the morning, people would see traces of sin on their faces and would know what type of sin they committed. How will it be with us if that is our situation today? In their time, when any impurity touched their cloth, they had to cut off the affected portion. Water was not enough to cleanse the Najaasah.

Loot at us today; we sin by day and night. Allah will stretch out His hands so that the sinners of the day might repent; He also stretches His Hands by night to receive the repentance of sinners of that period. Only one sentence suffices: As tagfirullaah!

110. Yet whoso doeth evil or wrongeth his own soul, then seeketh pardon of Allah, will find Allah Forgiving, Merciful. (An-Nisaa)