Allah, the Wise, has said:
وَ مَا مِنْ دَآبَّةٍ فِي الأََرْضِ إِلاَّ عَلَى اللهِ رِزْقُها
"And there is no creature on the earth but on Allah is the sustenance of it." 
The Noble Prophet (s.a.w) said:
أََلرِّزْقُ يَطلُبُ الْعَبْدَ أَشَدُّ طَلَباً مِنْ أَجَلِهِ
"Sustenance seeks a person more intensely than his death does." 
There exists no creature except that Allah has apportioned a livelihood for it, and no soul departs from the world before it has consumed the last morsel that had been ordained for it. One should strive to procure lawful sustenance and, in the event of delay and stoppages in this path, desist from attempting to obtain it by unlawful means - the best approach being that of patience and self-control.
Every person has his sustenance placed in a particular thing - one has his sustenance placed in trade, while another has it in leadership while yet another in farming, etc. Absence of satisfaction with respect to the share allotted, and lack of contentment strengthens the vices of greed and covetousness within man leading him towards sins in order to procure an increased sustenance - a state that only stems from a lack of Tawakkul) in Allah.
1 – They Should Witness the Wisdom!
Prophet Musa (a.s) came across a poor person who, due to his abject poverty, lay bare-bodied on the desert sand. When he (a.s) came nearer, the person requested: "O' Musa! Pray to Allah that he grants me a little sustenance for I am on the verge of dying."
Musa (a.s) prayed for him and then proceeded from there to Mount Sinai to converse with Allah.
A few days later Musa (a.s), on his return, happened to pass by that very place when he witnessed that the same poor man had been arrested and a large crowd had gathered around him.
He (a.s) inquired: "What has happened?" The people present there said: "Until recently he was penniless but off late he had managed to acquire some money; having consumed wine, he got involved in a brawl and killed a person. He has now been arrested so that he can be subjected to 'qisas') and put to death!"
Allah says in the Noble Qur'an:
وَ لَوْ بَسَطَ اللٌّهُ الرِّزْقَ لِعِبادِهِ لَبَغَوْا فِي الأَرْضِ
"And if Allah should amplify the provision for His servants they would certainly revolt in the earth."
Musa (a.s) acknowledged the divine Wisdom and, expressing repentance over his request, sought Allah's forgiveness.
2 – Incorrect Deduction from The Qur'an
Umar Ibn Muslim was one of the companions of Imam Sadiq (a.s) and used to visit him (a.s) frequently.
Once, when he did not visit the Imam (a.s) for a long time, he (a.s) inquired about him from Ali Ibn Abdul Aziz, who said: "May I be made your ransom! He has stopped working for his livelihood, and has engaged himself in worship and asceticism instead. Hearing this, Imam Sadiq (a.s) said: "Woe unto him! But does he not know that the prayers of one, who stops working, go unanswered!"
During the time of the Noble Prophet (s.a.w), when the verse:
وَ مَنْ يَتَّقِ اللٌّهَ يَجْعَلْ لَهُ مَخْرَجاً وَ يَرْزُقْهُ مِنْ حَيْثُ لا يَحْتَسِبُ
"And whoever is careful of (his duty to) Allah, He will make for him an outlet, and give him sustenance from whence he thinks not" was revealed, a group from amongst the Muslims abandoned their professions, adopted seclusion and engaged themselves in worship, saying: "Allah Himself provides the sustenance and shall never permit the religious ones to become distressed and destitute; hence why do we need to toil in order to procure our sustenance."
When the Noble Prophet (s.a.w) was informed of this, he (s.a.w) summoned them and objecting at this attitude of theirs, asked: "Why have you abandoned your professions?" They replied: "Allah has undertaken to provide us our sustenance." When he (s.a.w) heard this, he explained: "It is not as you think. Allah does not answer the prayers of a person who, despite possessing the ability to work and exert himself, fails to do so. You must continue to engage yourselves in your respective professions."
3 – Sustenance in the Measure of Sufficiency
Once, passing through a desert, the Noble Prophet (s.a.w) and his companions happened to come across a person tending camels and requested him to provide them with some milk. The man excused himself saying: "The milk that is in the breasts of these camels is for the breakfast of the people of the tribe and that, which lies in the container, is for their evening meals."
When he heard this, the Noble Prophet (s.a.w) prayed for him, saying: "O' Lord! Increase this person in wealth and children" - and the group continued on its way. A little later they came across another person, who too was engaged in feeding the camels. When they requested him to provide them with some milk, he immediately milked the she-camels and poured all of the milk in the vessels of the Noble Prophet's (s.a.w). In addition to the milk he even presented them with a sheep and said: At the moment this is all I can offer but if you desire I shall arrange for more.
The Noble Prophet (s.a.w) raised his holy hands and prayed: "O' Lord! Grant him sustenance in a measure that is sufficient for him."
Astonished, his (s.a.w) companions said: "O' Prophet of Allah! For the person who rejected your request you sought something which all of us long for, whereas for the one who fulfilled your desire, you prayed for something, which none of us prefer (sustenance in a measure that is just sufficient and not excess)!"
The Noble Prophet (s.a.w) said:
إِنَّ مَا قَلَّ وَ كَفَى خَيْرٌ مِمَّا كَثُرَ وَ أَلْهَى
"A livelihood that is less but sufficient for (fulfilling the needs of) one's life is better than great riches that engrosses man in itself." He (s.a.w) then supplicated:
اللَّهُمَّ ارْزُقْ مُحَمَّداً وَ آلَ مُحَمَّدٍ الْكَفَافَ
"O' Lord! Grant Muhammad and his Progeny a sustenance in the measure that is just sufficient (for them).
4 – Charity Increases Sustenance
Imam Sadiq (a.s) had many sons, one of whom was named Muhammad. Occasionally it would so happen that his income would exceed his expenses. Once, Imam Sadiq (a.s) inquired: "How much have you managed to save?" He replied: "Forty dinars." The Imam (a.s) said: "Give it as charity in the way of Allah. He said: This is all that I have with me and if I were to give this in charity there would be nothing left for me."
The Imam (a.s) insisted: "Go and give it in charity and Allah shall compensate it for you. Do you not know that for everything there is a key and the key to sustenance is charity?"
Muhammad, heeding his father's advice, gave the forty dinars in charity. Hardly ten days had passed by since this episode when a sum of four thousand dinars was presented to the Imam (a.s). Turning to Muhammad, he (a.s) said: "My Son! We gave forty dinars in the path of Allah and He gave us four thousand dinars (a hundred times) in return."
5 – Wealth from Unknown Places
The Buyids, whose sultanate had commenced in the year 322 ah, ruled for a period of 126 years. The greatest of the Buyid rulers and the most compassionate of them all with respect to the Shiite faith and his subjects was Imad al-Daulah - (Abul Hasan, Ali Ibn Babwaih) - who ruled for nine years (d. 338 ah). During his lifetime, several strange incidents occurred with him in connection with riches and treasures:
1. When Imad al-Daulah arrived in Shiraz, Yaqut, whom Al-Muqtadir Billah Abbasi had placed there as the governor, took to flight. In the circumstances, Imad al-Daulah did not possess anything to pay for the expenditure of his army. Distressed and lost in thought he set out for hunting. On the way the foot of his horse plunged into a hole. As Imad al-Daulah extracted the animal's foot, the hole widened revealing a treasure which Yaqut had concealed there. He extracted the treasure and used it to pay for his army's expenses.
2. Once, as he lay down and reflected about his army and subjects, his eyes suddenly fell upon a snake that had emerged from one corner of the roof and disappeared into another. As a precautionary measure, he ordered the roof to be taken apart and the snake killed so that it did not sting anyone.
When a portion of the roof was broken, a second roof became manifest and the intervening region betwin the two roofs was found to house chests containing a total of five hundred thousand dinars. The chests were brought down and Imad al-Daulah distributed the money amongst his subjects.
3. Once, having decided to have some clothes stitched for the elders of his army, his soldiers and himself, he called for a tailor. The special tailor of Yaqut, the erstwhile governor of the city, was recommended to him. Incidentally this tailor happened to be deaf but Imad al-Daulah said: "The faculty of sight is what a tailor ought to necessarily possess; as for hearing, it is not a necessity."
When the tailor was brought before him, he ordered: "I want you to stitch clothes for my servants, soldiers, officers, generals and myself."
The tailor - deaf that he was - imagined that someone had spoken ill of him and, complaining that he had money in his possession, said: "There are only four chests of the governor Yaqut in my custody and I am unaware of what is contained within them!"
Imad al-Daulah ordered the chests to be brought before him; when they were opened, they were found to contain great riches, beautiful clothes and valuable stones.
 Surat Hud (11), Verse 6
 Jame~ul Akhbar, pg. 126
 Placing one’s trust (in Allah) (Tr.
 Retaliation (Tr.
 Suratul Shura (42), Verse 27
 Hikayat-ha-e-Gulistan, pg. 161
 Suratul ±alaq (65), Verse 2-3
 Ba Mardum In Guneh Barkhord Konim, pg. 163; al-Wafi, vol. 10, pg. 15
 Dastan-ha Wa Pand-ha, vol. 2, pg. 72; Anwar al-Nu~maniyyah, pg. 342
 Hikayat-ha-e-Shanidani, vol. 4, pg. 92; Al-Kafi, vol. 4, pg. 9
 Jame’ al-Nurain, pg. 323. It has been reported in the book ‘Akhbar-e-Ghaibiyyah dar malahim wa fitan’ (pg. 314), that Amirul Mo’minin (a.s), alluding to the rule of the Buyids, had stated: يخرج من ديلمان بنو الصياد … ثم يستقوي امرهم حتى يملكوا الزوراء و يخلعوا الخلفاء