Allah expands the sustenance for whomsoever He desires and straitens it for whomsoever He desires. (Noble Qur’an, 13:26)
One day Hadrat Ali Murtada (as) went to a Mosque (Masjid) to say his Prayers (Salat). Hadrat Ali Murtada (as) asked a man standing nearby to look after his Horse. When Hadrat Ali Murtada (as) came out, he had two dirhams in his hand which he (as) intended to give to that man as reward. But that man was nowhere to be seen. Hadrat Ali Murtada (as) came to the Horse and found that his rein was missing.
Hadrat Ali Murtada (as) went to the market to buy another rein. Hadrat Ali Murtada (as) went to a shop where he (as) found the exact rein that had gone missing. Hadrat Ali Murtada (as) recognized the rein as it was his own and asked the shopkeeper the price of that rein.
Shopkeeper: A man had just been to my shop and sold this rein to me for two dirhams. You can have it for the same price.
Hadrat Ali Murtada (as): Showing him the two dirhams that he was holding in his hands and said, "This man did me a favour of looking after my Horse. So, I decided to give him two dirhams in return. He could not wait to get this lawfully. Instead he robbed and sold it you. He still got the same amount of money and not a penny more! His anxiety did not increase his wages at all and made him a criminal into the bargain."
Sometimes people become so greedy that in order to obtain their sustenance, they would do anything. What they fail to understand is that Allah (SWT) has already destined their sustenance (Rizq). Now whether he earns it lawfully (Halaal) or unlawfully (Haram), begs or steals or gambles, he is not going to get anything more.
The only difference is that if you earn lawfully, you will have to give account to Allah (SWT) and if you earn it unlawfully, there is a punishment for it.