[فَلْيَحْذَرِ الَّذِينَ يُخَـلِفُونَ عَنْ أَمْرِهِ]

(And let those beware who oppose the Messenger's commandment) This means going against the commandment of the Prophet , which is his way, methodology and Sunnah. All words and deeds will be measured against his words and deeds; those that are in accordance with his words and deeds will be accepted, and whatever does not match up will be rejected, no matter who the person is who said and did them. It was recorded in the Two Sahihs and elsewhere that the Messenger of Allah said:

«مَنْ عَمِلَ عَمَلًا لَيْسَ عَلَيْهِ أَمْرُنَا فَهُوَ رَدٌّ»

(Whoever does a deed that is not in accordance with this matter of ours will have it rejected.) meaning, let those beware who go against the Shari`ah of the Messenger , in secret and in the open,

[أَن تُصِيبَهُمْ فِتْنَةٌ]

(lest some Fitnah should befall them), i.e., lest some disbelief or hypocrisy or innovation enter their hearts.

[أَوْ يُصِيبَهُمْ عَذَابٌ أَلِيمٌ]

(or a painful torment be inflicted on them.) means in this world afflicting them with capital punishment, or by law of prescribed punishment, or by confinement in prison, or so on. Imam Ahmad recorded that Abu Hurayrah said, "The Messenger of Allah said:

«مَثَلِي وَمَثَلُكُمْ كَمَثَلِ رَجُلٍ اسْتَوْقَدَ نَارًا فَلَمَّا أَضَاءَتْ مَا حَوْلَهَا جَعَلَ الْفَرَاشُ وَهَذِهِ الدَّوَابُّ اللَّائِي يَقَعْنَ فِي النَّارِ يَقَعْنَ فِيهَا، وَجَعَلَ يَحْجُزُهُنَّ وَيَغْلِبْنَهُ فَيَقْتَحِمْنَ فِيهَا قَالَ: فَذَلِكَ مَثَلِي وَمَثَلُكُمْ، أَنَا آخِذٌ بِحُجَزِكُمْ عَنِ النَّارِ هَلُمَّ عَنِ النَّارِ، فَتَغْلِبُونِي وَتَقْتَحِمُونَ فِيهَا»

n(The parable of me and you is as the example of a man who kindled a fire and when it illuminated all around him, moths and other creatures started falling into the fire, and he was trying to stop them but they overwhelmed him and still kept falling in. This is the parable of me and you. I am trying to restrain you and keep you away from the fire, but you overwhelm me and fall in.) This was also narrated by Al-Bukhari and Muslim.

[أَلا إِنَّ للَّهِ مَا فِى السَّمَـوَتِ وَالاٌّرْضِ قَدْ يَعْلَمُ مَآ أَنتُمْ عَلَيْهِ وَيَوْمَ يُرْجَعُونَ إِلَيْهِ فَيُنَبِّئُهُمْ بِمَا عَمِلُواْ وَاللَّهُ بِكُلِّ شَىْءٍ عَلِيمُ ]

(64. Certainly, to Allah belongs all that is in the heavens and the earth. Indeed, He knows your condition and the Day when they will be brought back to Him, then He will inform them of what they did. And Allah is All-Knower of everything.)