Assalamualaikum w.b.t. Islam prohibits us from being wasteful but what is the true meaning of being wasteful?
Alhamdulillah, praise and gratitude to Allah SWT for His countless blessings for us all. Praise and salutations to our beloved Prophet Muhammad PBUH, his family, companions and all those who follow his footsteps until the Last Day.
Wastefulness or being extravagant is a characteristic of a person who is being excessive or transgressing. This despicable characteristic is firmly warned against by Allah SWT where He states:
وَلَا تُبَذِّرْ تَبْذِيرًا (٢٦﴾ إِنَّ الْمُبَذِّرِينَ كَانُوا إِخْوَانَ الشَّيَاطِينِ ۖ وَكَانَ الشَّيْطَانُ لِرَبِّهِ كَفُورًا
“And do not spend wastefully. Indeed, the wasteful are brothers of the devils, and ever has Satan been to his Lord ungrateful.” 
Imam Ibn Kathir in his commentary said: “The meaning of brothers of the devils means it is a characteristic similar to them, (that love to be wasteful and extravagant).” 
Furthermore, the Prophet PBUH once advised in a hadith that states the prohibition of israf (excessive) in using water even in performing ablution. This is based on a narration from Abdullah bin ‘Amr bin al-‘Ash R.Anhuma, he said:
أَنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ مَرَّ بِسَعْدٍ وَهُوَ يَتَوَضَّأُ فَقَالَ ” مَا هَذَا السَّرَفُ ” . فَقَالَ أَفِي الْوُضُوءِ إِسْرَافٌ قَالَ ” نَعَمْ وَإِنْ كُنْتَ عَلَى نَهَرٍ جَارٍ
The Messenger of Allah passed by Sa’d when he was performing ablution, and he said: ‘What is this extravagance?’ He said: ‘Can there be any extravagance in ablution?’ He said: ‘Yes, even if you are on the bank of a flowing river.'” 
The hadith clearly shows that the act of israf and being wasteful in performing ablution is clearly rebuked and prohibited by Rasullullah PBUH. Even if there is a large volume of water available such as when one is at the beach, river and others.
Syeikh Mulla Ali al-Qari Rahimahullah when commenting on this hadith said: He is being israf when performing ablution is the same as increasing the number of washings for more than three washings, or being israf in terms of increasing the water usage from what is necessary.
He also said: There is nothing good out of israf (being excessive) and there is no israf in good. He (Abdullah bin Amru) thought that there is no israf when it comes to matters of obedience and worship. Then the Prophet PBUH answered: “Yes, there is israf. Even if you are on the bank of a flowing river.” The reason is in these actions there is israf in time and being wasteful of one’s age. Or being excessive from the syar’ie limits (when performing ablution) as previously stated. 
Definition of being wasteful
Some scholars stated that israf and being extravagant are words that have the same meaning. However, some scholars differentiate the meaning of these two words. This is as stated by Imam al-Jurjani: Israf is the usage of something excessively or more than necessary. While wasteful is the usage of unnecessary things. 
Wasteful originates from an Arabic word that means using wealth in an unbeneficial way and will not be rewarded or misplacing the rights of giving. 
Ibn Kathir cited the opinion of Qatadah in defining wastefulness: Wastefulness is spending on matters of sin that is prohibited by Allah SWT and not the rights or bad matters. 
While spending on good matters, beneficial, matters that will be rewarded by Allah and obedience are encouraged as long as it doesn’t affect or harm the person who is spending.
Mujahid in stating about wastefulness said: “If a person spends his hill of wealth in obedience towards Allah SWT, then he isn’t included as those who are excessive. And if he spends one dirham in sin towards Allah then he is amongst those who are excessive.” 
Types of wastefulness
- Wasteful in spending
Sinful spending is spending on wrong, bad or prohibited matters. Sinful spending can be seen from two angles: prohibited spending and spending that its usage can distract people from remembering or obeying the commandments of Allah SWT.
This is like spending on something that can lead to harm to its user or society such as liquor. Liquor can harm the mind and brain function of its drinker and concurrently harms a society with crimes that are a result of drinking. Likewise, for gambling, prostitution and others.
Sports for the purpose of maintaining one’s health are encouraged in Islam. However, if one plays non-stop or the sport takes a long time or the ending of the game will force the player to leave his obligatory prayer or the game involves an excessive amount of money that he neglects his zakat obligation, then it is considered a sin. This first type of spending is clear and easy to identify and avoid.
- Spending to be boastful
Boastfulness in one’s spending is usually related to spending on luxury items. These luxury items are not a necessity or it isn’t used to help ease one’s life, rather their main purpose is their prestige, modern lifestyle, extravagance, boastfulness and arrogance.
Islam places such an attitude as riya’ and it is prohibited in Islam for it is a form of shirk (minor). Imam Fakhruddin al-Razi explained that riya’ is showcasing something in one’s heart so that people see him as a religious person. 
The Prophet PBUH explained the meaning of riya’. This is stated in a hadith narrated by Mahmud bin Labid where Rasullullah PBUH said:
إِنَّ أَخْوَفَ مَا أَخَافُ عَلَيْكُمْ الشِّرْكُ الْأَصْغَرُ قَالُوا وَمَا الشِّرْكُ الْأَصْغَرُ يَا رَسُولَ اللَّهِ قَالَ الرِّيَاءُ يَقُولُ اللَّهُ عَزَّ وَجَلَّ لَهُمْ يَوْمَ الْقِيَامَةِ إِذَا جُزِيَ النَّاسُ بِأَعْمَالِهِمْ اذْهَبُوا إِلَى الَّذِينَ كُنْتُمْ تُرَاءُونَ فِي الدُّنْيَا فَانْظُرُوا هَلْ تَجِدُونَ عِنْدَهُمْ جَزَاءً
“The matter I fear most for you is the minor shirk. The companions then asked: What is this minor shirk O Messenger of Allah? The Prophet PBUH answered: It is Riya’. Allah SWT will declare on the Day of Judgement: Go to those who you want to boast to in the world and see if there are rewards from them (of your deeds).” 
Syeikh Farid al-Ansari divided riya’ into several parts. That is riya’ in religion, body, speech, actions and others which are:
- Riya’ in religion is showcasing his leanness or neatness so that people see him as a person who works very hard in his worship and as though he is prepared to face the hereafter.
- Riya’ in speech is giving advice and reminders with the intention of showcasing his concern towards the welfare of Muslims or loudly reciting dhikr in front of others.
- Riya’ in actions is like showcasing long qiyam and rukuk when praying in front of others.
However, the reality of being boastful is not limited to one’s spending on luxury goods, but it can also happen on other simple goods such as one’s basic needs, as long as there is the intention of showing off when using them. This second type of spending is also pretty easy to be identified.
- Worthless spending
Worthless spending is spending on halal matters excessively or more than necessary. This is unreasonable spending too for it is still considered wasteful. The excess items will spoil and be neglected when actually there are others who are in need of them and others can benefit from the items if they are given away. This type of spending is a little difficult to be identified and measured. Hence, we are advised to always be careful and vigilant so as to not fall into worthless spending.
To conclude, we state that the act of being wasteful should be avoided. The reason, this act clearly contradicts the principles of Islam that are to be fair with the wealth we own and place it where it should be.
Lastly, may Allah SWT grant us all understanding in this religion. Amin.
 Surah al-Isra’ : 26-27
 See Tafsir al-Quran al-Adzim, 3/48
 Riwayat Ibn Majah (425), Ibn Hajar al-Asqalani in al-Talkhis al-Habir stated the sanad is dhaif (1/224), while Imam ‘Alau al-Din in Syarh Sunan Ibn Majah said sanad is dhaif and the meaning of the hadith, the sanad is sahih (1/325)
 See Mirqat al-Mafatih, 2/421
 See Al-Ta’rifat, pg. 24
 See Daur al-Qaim wa al-Akhlak fi al-Iqtishad al-Islami, pg. 253-254
 See Tafsir Ibn Kathir, 5/69
 See Daur al-Qaim wa al-Akhlak fi al-Iqtishad al-Islami, pg. 255
 See Mafatih al-Ghaib, 32/301
 Riwayat Ahmad (23630) in his Musnad. Ibn Hajar al-Asqalani in Bulugh al-Maram (330) stated the sanad of this hadith Hasan.