Hadith: You have asked me about a great matter, which is, indeed, easy for whomever Allah makes it easy

عَنْ مُعَاذِ بْنِ جَبَلٍ رضي الله عنه قَالَ:
كُنْتُ مَعَ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فِي سَفَرٍ، فَأَصْبَحْتُ يَوْمًا قَرِيبًا مِنْهُ وَنَحْنُ نَسِيرُ، فَقُلْتُ: يَا رَسُولَ اللهِ أَخْبِرْنِي بِعَمَلٍ يُدْخِلُنِي الجَنَّةَ وَيُبَاعِدُنِي عَنِ النَّارِ، قَالَ: «لَقَدْ سَأَلْتَنِي عَنْ عَظِيمٍ، وَإِنَّهُ لَيَسِيرٌ عَلَى مَنْ يَسَّرَهُ اللَّهُ عَلَيْهِ، تَعْبُدُ اللَّهَ وَلاَ تُشْرِكْ بِهِ شَيْئًا، وَتُقِيمُ الصَّلاَةَ، وَتُؤْتِي الزَّكَاةَ، وَتَصُومُ رَمَضَانَ، وَتَحُجُّ البَيْتَ» ثُمَّ قَالَ: «أَلاَ أَدُلُّكَ عَلَى أَبْوَابِ الخَيْرِ: الصَّوْمُ جُنَّةٌ، وَالصَّدَقَةُ تُطْفِئُ الخَطِيئَةَ كَمَا يُطْفِئُ الْمَاءُ النَّارَ، وَصَلاَةُ الرَّجُلِ مِنْ جَوْفِ اللَّيْلِ» قَالَ: ثُمَّ تَلاَ: «{تَتَجَافَى جُنُوبُهُمْ عَنِ الْمَضَاجِعِ}، حَتَّى بَلَغَ {يَعْمَلُونَ}» ثُمَّ قَالَ: «أَلاَ أُخْبِرُكَ بِرَأْسِ الأَمْرِ كُلِّهِ وَعَمُودِهِ، وَذِرْوَةِ سَنَامِهِ؟» قُلْتُ: بَلَى يَا رَسُولَ اللهِ، قَالَ: «رَأْسُ الأَمْرِ الإِسْلاَمُ، وَعَمُودُهُ الصَّلاَةُ، وَذِرْوَةُ سَنَامِهِ الجِهَادُ» ثُمَّ قَالَ: «أَلاَ أُخْبِرُكَ بِمَلاَكِ ذَلِكَ كُلِّهِ؟» قُلْتُ: بَلَى يَا نَبِيَّ اللهِ، فَأَخَذَ بِلِسَانِهِ قَالَ: «كُفَّ عَلَيْكَ هَذَا» فَقُلْتُ: يَا نَبِيَّ اللهِ، وَإِنَّا لَمُؤَاخَذُونَ بِمَا نَتَكَلَّمُ بِهِ؟ فَقَالَ: «ثَكِلَتْكَ أُمُّكَ يَا مُعَاذُ، وَهَلْ يَكُبُّ النَّاسَ فِي النَّارِ عَلَى وُجُوهِهِمْ أَوْ عَلَى مَنَاخِرِهِمْ إِلاَّ حَصَائِدُ أَلْسِنَتِهِمْ».
[صحيح بمجموع طرقه] - [رواه الترمذي وابن ماجه وأحمد] - [سنن الترمذي: 2616]

Mu‘ādh ibn Jabal (may Allah be pleased with him) reported:
I was on a journey in the company of the Prophet (may Allah's peace and blessings be upon him). One morning I was close to him when we were on the move, so I said: O Messenger of Allah, inform me of a deed that admits me to Paradise and keeps me far from Hellfire. He said: "You have asked me about a great matter, which is, indeed, easy for whomever Allah makes it easy. Worship Allah and do not associate anything with Him, establish the prayer, give Zakah, fast Ramadan, and make Hajj to the House." Then he said: "Shall I not guide you to the gates of goodness? Fasting is a shield, charity extinguishes sin as water extinguishes fire, and a man's prayer in the dead of night." He said: Then he recited: "{They forsake their beds} until he reached {what they used to do} [Surat as-Sajdah:  16-17]." Then he said: "Shall I inform you of the head of the whole matter, its pillar, and its peak?" I said: Yes, O Messenger of Allah. He said: "The head of the matter is Islam, its pillar is the prayer, and its peak is Jihad." Then he said: "Shall I inform you of what holds all these things?" I said: Yes, O Prophet of Allah. So he took hold of his tongue and said: "Keep this under control." I said: O Prophet of Allah, are we held accountable for what we speak? He said: "May your mother lose you, O Mu‘ādh! What else casts people into Hellfire on their faces or on their noses other than the harvest of their tongues?"
[Authentic by overall chains of narrators] - [Narrated by At-Termedhy & Ibn Majah & Ahmad] - [Sunan At-Termedhy - 2616]

Explanation

Mu‘ādh (may Allah be pleased with him) said: I was on a journey in the company of the Prophet (may Allah's peace and blessings be upon him). One morning, I was close to him when we were on the move, so I said: O Messenger of Allah, inform me of a deed that admits me to Paradise and keeps me far from Hellfire. He said: You have asked me about a deed that is hard for people to perform, but it is, indeed, easy and simple for whomever Allah makes it easy. Perform the obligations of Islam.
First: Worship Allah alone and do not associate anything with Him.
Second: Establish the five obligatory prayers every day and night, namely Fajr, Zhuhr, ‘Asr, Maghrib, and ''Ishā'—along with observing their conditions, pillars, and obligatory acts.
Third: Pay the obligatory Zakah, which is an obligatory financial act of worship due on every type of property that has reached the limit prescribed by the Shariah, and it is to be given to those entitled to it.
Fourth: Fast Ramadan, which is abstaining from food, drink, and other fast invalidators as a form of worship from the break of dawn to sunset.
Fifth: Make Hajj to the House by heading for Makkah to perform the rituals as a means of worshiping Allah Almighty.
Then he (may Allah's peace and blessings be upon him) said: Shall I inform you of the path leading to the gates of goodness? Follow these obligations with voluntary acts of worship.
First: Voluntary fast, which prevents from falling into sins by breaking the lust and enfeebling the power.
Second: Voluntary charity extinguishes the sin after being committed, eliminates it, and erases its traces.
Third: Tahjjud prayer during the last third of the night, then he (may Allah's peace and blessings be upon him) recited Allah's statement: {They forsake their beds}, i.e., they leave their beds {invoking their Lord} in prayer, Dhikr, recitation of the Qur’an, and supplication {with fear and hope, and spend out of what We have provided for them. No soul knows what delights are kept hidden for them}, i.e., the bliss that will provide them with ultimate comfort on the Day of Judgment and in Paradise {as a reward for what they used to do.}
Then he (may Allah's peace and blessings be upon him) said: Shall I inform you of the essence of the religion, its pillar upon which it is founded, and its peak?
Mu‘ādh (may Allah be pleased with him) said: Yes, O Messenger of Allah.
The Prophet (may Allah's peace and blessings be upon him) said: The head of the matter is: Islam, i.e., the two testimonies of faith by which one attains the essence of the religion. Its pillar is: the prayer, since there is no Islam without prayer as there is no house without a pillar. So, whoever prays, his religion is enhanced and elevated. Its peak and climax are attained through Jihad and the exertion of effort in fighting against the enemies of the religion to make the word of Allah supreme.
Then he (may Allah's peace and blessings be upon him) said: Shall I tell you what controls and perfects the aforementioned? He (may Allah's peace and blessings be upon him) took hold of his tongue and said: Control this and do not speak about what does not concern you. Mu‘ādh said: Does our Lord hold us accountable and responsible and punish us for what we speak?!
He (may Allah's peace and blessings be upon him) said: May your mother lose you! This is not meant as a supplication against him; rather, it is one of the Arabs' common expressions that is meant to draw attention to something that one is supposed to be aware of and to know. Then he said: What else can cast people and throw them on their faces in Hellfire other than the harvest of their tongues speaking words of disbelief, accusing of immorality, insult, backbiting, talebearing, false accusation, etc.?!