Anything that can potentially be mixed with something else, when it is purified and separated from such mixtures, is called "pure." Sincerity (Ikhlas) is the opposite of associating partners (Shirk). Thus, whoever lacks sincerity is engaging in shirk, though shirk has varying degrees. Sincerity in monotheism is opposed by shirk in divinity.

Sincerity and its opposite reside in the heart; their place is within the heart. This pertains to intentions and purposes. Hence, the Prophet (PBUH) referred all actions back to intentions, saying: " Deeds are to be judged only by intentions, and a man will have only what he intended." [Agreed upon].

As for the ruling on sincerity, Allah The Exalted Says (What means): "And they have been commanded no more than this: To worship God, offering Him sincere devotion, being true (in faith); to establish regular prayer; and to practise regular charity; and that is the Religion Right and Straight. " [Al-Bayyina/5]. He also Says (What means): "Is it not to God that sincere devotion is due? But those who take for protectors other than God (say): "We only serve them in order that they may bring us nearer to God." Truly God will judge between them in that wherein they differ. But God guides not such as are false and ungrateful. " [Az-Zumar/3]. Moreover, He Says (What means): "Except for those who repent, mend (their lives) hold fast to God, and purify their religion as in God’s sight: if so they will be (numbered) with the believers. And soon will God grant to the believers a reward of immense value. " [An-Nisa/146].

Regarding the virtue of sincerity, the Prophet (PBUH) said: "There are three things on account of which no rancour enters a Muslim's heart: sincere action for Allah’s sake, good counsel to Muslims, and holding fast to their community." [At-Tirmithi & Ibn Majah].

In warning against showing off (Riyā') and lacking sincerity, the Prophet (PBUH) said: "The first person to be judged on the day of resurrection will be a man who died as a martyr. He will be brought forward, and after Allah has reminded him of the favour He showed him and the man acknowledges it, He will ask: "What did you do to show gratitude for it? "

 

 The man will reply: "I fought for Thy cause till I was martyred. " Allah will Say: "You lie. You fought that people might call you courageous, and they have done so. "Command will then be issued about him, and he will be dragged on his face and thrown into hell. Next, a man who has acquired and taught knowledge and read the Qur’an will be brought forward, and after Allah has reminded him of the favour He showed him and the man acknowledges it, He will ask: "What did you do to show gratitude for it? "  The man will reply: "I acquired and taught knowledge and read the Qur’an for Thy sake. " Allah will Say: "You lie. You acquired knowledge that people might call you learned, and you read the Qur’an that they might call you a reader, and they have done so. " Command will then be issued about him, and he will be dragged on his face and thrown into hell. Next a man whom Allah has made affluent and whom He has given all kinds of property will be brought forward, and after Allah has reminded him of the favour He showed him and the man acknowledges it, He will ask: "What did you do to show gratitude for it? "The man will reply: "I have not neglected to give liberally for Thy sake to all the causes approved by Thee for this purpose. " Allah will say: "You lie. You did it that people might call you generous, and they have done so.’ Command will then be issued about him, and he will be dragged on his face and thrown into hell. " [Muslim].

Islam emphasizes sincerity in worship in numerous verses of the Qur'an. Among them is Allah's Statement (What means): "Verily it is We Who have revealed the Book to thee in Truth: so serve God, offering Him sincere devotion. " [Az-Zumar/2]. Charity is also only considered valid when it is free from selfish motives and solely for the sake of Allah: "(Saying),"We feed you for the sake of God alone: no reward do we desire from you, nor thanks. " [Al-Insan/9]. Allah also describes the ultimate sincerity and its rewards: "But those most devoted to God shall be removed far from it,- Those who spend their wealth for increase in self-purification, And have in their minds no favour from anyone for which a reward is expected in return, But only the desire to seek for the Countenance of their Lord Most High; And soon will they attain (complete) satisfaction."[Al-Layl/17-21].

Detachment from desires, correcting the inclinations of the heart, purifying intentions, and dedicating the heart sincerely to The Lord of all worlds elevate the status of worldly deeds, transforming them into accepted acts of worship. The Messenger of Allah (peace and blessings be upon him) said to Sa'd Ibn Abi Waqqas (may Allah be pleased with him): "You will be rewarded for whatever you spend for Allah's sake even if it were a morsel which you put in your wife's mouth." [Bukhari].

A Muslim may be rewarded for an act they did not perform. During the Battle of Tabuk, when some Muslims could not participate due to the Prophet's (PBUH) inability to equip them, and given their deep desire to sacrifice and their sincere intentions, the noble Messenger said to his army: "In Medina, there are men who, every time you crossed a valley or travelled a road, they shared with you in the reward. They were kept behind by (legitimate) excuses. " [Agreed upon]. Thus, their sincere intention granted them the reward of the Mujahedeen!

A righteous intention is the solid foundation upon which good deeds are built. Allah warns in the Qur'an: "O ye who believe! cancel not your charity by reminders of your generosity or by injury,- like those who spend their substance to be seen of men, but believe neither in God nor in the Last Day. They are in parable like a hard, barren rock, on which is a little soil: on it falls heavy rain, which leaves it (Just) a bare stone. They will be able to do nothing with aught they have earned. And God guideth not those who reject faith." [Al-Baqarah/264]. He also Says (What means): "So woe to the worshippers Who are neglectful of their prayers, Those who (want but) to be seen (of men)." [Al-Ma'un/4-6].

How precious sincerity is, and how abundant its blessings! It can be found in the smallest of actions, yet it multiplies to the extent that it outweighs mountains, while much can be devoid of sincerity and hold no weight with Allah. Intention precedes action, and the inner state precedes the outward form. The Prophet (PBUH) said: "Indeed, Allah does not look at your bodies or your forms, but He looks at your hearts." [Moslim].

Whenever the soul is stirred by the desire for self-interest, the longing for status, and the wish to boast, the heat of sincerity gradually diminishes. Therefore, Allah loves deeds that are pure, free from any corrupting impurities: "Indeed, to Allah belongs the pure religion."

[Az-Zumar/3]. For this reason, Islam also fought against showing off (Riyaa), as narrated from the Prophet (PBUH):"Even a small amount of showing off is shirk." [Ibn Majah].

In conclusion, it is no wonder that Islam emphasizes sincerity and gives it such importance, because the believer's entire being belongs to Allah: his soul, his wealth, his family, his children, his worldly life, and his death. Allah says {what means}:"And I did not create the jinn and mankind except to worship Me." [Adh-Dhariyat/56]. They are not to worship wealth, status, or any human being... And all praise is due to Allah, The Lord of all The Worlds.