Tafsir of Al-Isra 17:29

This is a metaphor for prohibiting stinginess and excessive spending, and a command for moderation, which lies between extravagance and parsimony.

{Then you will sit blamed} You will become blamed before God, for the spendthrift is not pleasing to Him, nor to people. The needy person will say: "He gave to so-and-so and deprived me." The wealthy person will say: "He does not manage his livelihood well." And you will blame yourself when you are in need and regret what you have done.

{Regretful} Stranded, having nothing left. It is derived from hasr (exhaustion), as in "a journey exhausts the traveler" when it wears him out, or being exhausted by the act of begging.

Regarding Jabir: While the Messenger of God (ﷺ) was sitting, a boy came to him and said, "My mother asks you for a garment." He replied, "Wait until later, then come back to us." The boy went to his mother, and she told him, "Tell him: My mother asks you for the very garment you are wearing." He entered his house, took off his shirt, gave it to him, and sat there naked. Bilal gave the call to prayer, and they waited, but he did not come out for the prayer.

It is also said: He gave Al-Aqra’ bin Habis and ‘Uyaynah bin Hisn one hundred camels each. Then ‘Abbas bin Mirdas came and began to recite:

Do you place my spoils and the spoils of Al-‘Ubayd Between ‘Uyaynah and Al-Aqra’? Neither Hisn nor Habis Surpassed my grandfather in any gathering. And I was not inferior to either of them, And whoever you debase today shall not be raised.

He then said: "O Abu Bakr, cut his tongue off from me [by satisfying him]; give him one hundred camels." Then this verse was revealed:

{Indeed, your Lord extends provision for whom He wills and restricts [it]. Indeed He is, of His servants, Acquainted and Seeing.}