All forms of extravagance in worldly matters are evils; a believer must be moderate in all his affairs. He (Glorified and Exalted be He) told us about the status of the wasteful by saying: But spend not wastefully (your wealth) in the manner of a spendthrift.
Verily, the spendthrifts are brothers of the Shayâtîn (devils), and the Shaitân (DevilSatan) is ever ungrateful to his Lord.
The squanderer wastes money and should not be entrusted with it. Money has great status and good money is the best support for the righteous person to spend for the sake of Allah.
It is obligatory to preserve money and not to waste it, therefore, stress was made concerning perjury because it leads to taking money, bloodshed, and dishonoring without right. The Prophet (peace be upon him) said: Shall I tell you about the most grievous of the major sins? We said: Yes, O Messenger of Allah. He said: associating others with Allah and disobedience to parents. He was reclining then sat properly and said:
beware of perjury, beware of perjury. So the Prophet (peace be upon him) repeated the phrase several times because perjury contains great evil and bad consequences by which money is taken without right, souls are taken away, and honors are violated without right, therefore, the Prophet (peace be upon him) warned against it.
The warning is mentioned in the Qur'an as Allah (Glorified and Exalted be He) says in Surah AlHajj: So shun the abomination (worshipping) of idol, and shun lying speech (false statements)
As for disobedience to mothers, it is one of the major sins and a terrible crime which must be warned against and people should commend one another to avoid it. Those who commit Shirk (Polytheism) are committing the greatest sin as Allah (may He be Praised) says: And (remember) when Luqmân said to his son when he was advising him: "O my son! Join not in worship others with Allâh. Verily joining others in worship with Allâh is a great Zûlm (wrong) indeed. Allah (may He be Praised) says: Verily, Allâh forgives not that partners should be set up with Him (in worship), but He forgives except that (anything else) to whom He wills Back to the research on extravagance, Allah (may He be Praised and Glorified) says: But spend not wastefully (your wealth) in the manner of a spendthrift. Allah (may He be Praised) warns against extravagance i.e. improper and imprudent spending of money opposing the legal ways such as spending in oppressing people with the purpose of harming them or oppressing oneself by expenditure on intoxication, drugs, smoking, fornication, and all sins such as gambling, usury, etc. Thus, money will be wasted without reason such as overpurchasing of goods without need. This is a kind of wasting wealth and extravagance and the Messenger (peace be upon him) prohibited the waste of wealth.
So, extravagance is spending money in improper ways either on sins, or spending them in useless ways, such as wasting out of an indifference to money.
As for extravagance, it is the increase which has no reason. A person buys food and drink beyond his need. It is sufficient for him to buy a kilo of food or a kilo of meat or the like but a person gets more food and drink without need, then he throws the remaining in the garbage; this is called extravagance.
As for the destruction of money without right and spending them in improper ways of spending; it is called wasting. Allah (may He be Praised) explained that the wasteful people are the brothers of devils because they imitate them in play, wasting and sins.