Encouraging Khushu` and the Prohibition of imitating the People of the Scriptures
Allah asks,
أَلَمْ يَأْنِ لِلَّذِينَ امَنُوا أَن تَخْشَعَ قُلُوبُهُمْ لِذِكْرِ اللَّهِ وَمَا نَزَلَ مِنَ الْحَقِّ
Has not the time yet come for the believers that their hearts should be humble for the remembrance of Allah? And that which has been revealed of the truth,
Allah asks, `Has not the time come for the believers to feel humility in their hearts by the remembrance of Allah and hearing subtle advice and the recitation of the Qur'an, so that they may comprehend the Qur'an, abide by it, and hear and obey.
Muslim recorded that Abdullah bin Mas`ud said,
"Only four years separated our acceptance of Islam and the revelation of this Ayah, in which Allah subtly admonished us,
أَلَمْ يَأْنِ لِلَّذِينَ امَنُوا أَن تَخْشَعَ قُلُوبُهُمْ لِذِكْرِ اللَّهِ وَمَا نَزَلَ مِنَ الْحَقِّ
Has not the time yet come for the believers that their hearts should be humble for the remembrance of Allah"
This is the narration Muslim collected, just before the end of his book.
An-Nasa'i also collected this Hadith in the Tafsir of this Ayah.
Allah's statement,
وَلَا يَكُونُوا كَالَّذِينَ أُوتُوا الْكِتَابَ مِن قَبْلُ فَطَالَ عَلَيْهِمُ الاَْمَدُ فَقَسَتْ قُلُوبُهُمْ
Lest they become as those who received the Scripture before, and the term was prolonged for them and so their hearts were hardened,
Allah is prohibiting the believers from imitating those who were given the Scriptures before them, the Jews and Christians. As time passed, they changed the Book of Allah that they had, and sold it for a small, miserable price. They also abandoned Allah's Book behind their back and were impressed and consumed by various opinions and false creeds. They imitated the way others behaved with the religion of Allah, making their rabbis and priests into gods beside Allah. Consequently, their hearts became hard and they would not accept advice; their hearts did not feel humbled by Allah's promises or threats,
وَكَثِيرٌ مِّنْهُمْ فَاسِقُونَ
And many of them were rebellious.
meaning, in action;
therefore, their hearts are corrupt and their actions are invalid, just as Allah the Exalted said,
فَبِمَا نَقْضِهِم مِّيثَـقَهُمْ لَعنَّـهُمْ وَجَعَلْنَا قُلُوبَهُمْ قَاسِيَةً يُحَرِّفُونَ الْكَلِمَ عَن مَّوَضِعِهِ وَنَسُواْ حَظَّا مِّمَّا ذُكِرُواْ بِهِ
So, because of their breach of their covenant, We cursed them and made their hearts grow hard. They changed the words from their (right) places and have abandoned a good part of the Message that was sent to them. (5;13)
meaning, their hearts became corrupt and they hardened, and they acquired the behavior of changing Allah's Speech from their appropriate places and meanings. They abandoned acts of worship that they were commanded to perform and committed what they were prohibited to do.
This is why Allah forbade the believers from imitating them in any way, be it basic or detailed matters.
Allah the Exalted said,
اعْلَمُوا أَنَّ اللَّهَ يُحْيِي الاَْرْضَ بَعْدَ مَوْتِهَا
قَدْ بَيَّنَّا لَكُمُ الاْيَاتِ لَعَلَّكُمْ تَعْقِلُونَ