Hadith: Whoever shows hostility to a pious worshipper of Mine, I declare war against him. My slave does not draw near to Me with anything dearer to Me than what I have made obligatory for him

عَنْ أَبِي هُرَيْرَةَ رضي الله عنه قَالَ:
قَالَ رَسُولُ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ: «إِنَّ اللَّهَ قَالَ: مَنْ عَادَى لِي وَلِيًّا فَقَدْ آذَنْتُهُ بِالحَرْبِ، وَمَا تَقَرَّبَ إِلَيَّ عَبْدِي بِشَيْءٍ أَحَبَّ إِلَيَّ مِمَّا افْتَرَضْتُ عَلَيْهِ، وَمَا يَزَالُ عَبْدِي يَتَقَرَّبُ إِلَيَّ بِالنَّوَافِلِ حَتَّى أُحِبَّهُ، فَإِذَا أَحْبَبْتُهُ: كُنْتُ سَمْعَهُ الَّذِي يَسْمَعُ بِهِ، وَبَصَرَهُ الَّذِي يُبْصِرُ بِهِ، وَيَدَهُ الَّتِي يَبْطِشُ بِهَا، وَرِجْلَهُ الَّتِي يَمْشِي بِهَا، وَإِنْ سَأَلَنِي لَأُعْطِيَنَّهُ، وَلَئِنِ اسْتَعَاذَنِي لَأُعِيذَنَّهُ، وَمَا تَرَدَّدْتُ عَنْ شَيْءٍ أَنَا فَاعِلُهُ تَرَدُّدِي عَنْ نَفْسِ المُؤْمِنِ، يَكْرَهُ المَوْتَ وَأَنَا أَكْرَهُ مَسَاءَتَهُ».
[صحيح] - [رواه البخاري] - [صحيح البخاري: 6502]

Abu Hurayrah (may Allah be pleased with him) reported:
The Messenger of Allah (may Allah's peace and blessings be upon him) said: "Verily Allah said: Whoever shows hostility to a pious worshipper of Mine, I declare war against him. My slave does not draw near to Me with anything dearer to Me than what I have made obligatory for him. My slave continues to draw near to Me by doing supererogatory deeds until I love him. When I love him, I become his hearing with which he hears, his sight with which he sees, his hand with which he strikes, and his foot with which he walks. Were he to ask Me for something, I would surely give it to him, and were he to seek refuge with Me, I would surely grant him refuge. I do not hesitate to do anything as I hesitate to take the soul of the believer, for he hates death, and I hate to hurt him."
[Authentic hadith] - [Narrated by Bukhari] - [Sahih Bukhari - 6502]

Explanation

In the Qudsi Hadīth, the Prophet (may Allah's peace and blessings be upon him) informs that Allah Almighty said: Whoever hurts one of My pious worshippers, offends and hates him, I announce and declare enmity towards him.
"Waliyy" (pious worshipper) is the pious believer, and the slave's share of Allah's Wilāyah (being pious in worshiping Allah) depends on the degree of his faith and piety. A Muslim does not draw near to his Lord with anything dearer to Him than what He has prescribed and made obligatory upon him, performing acts of obedience and avoiding prohibitions. A Muslim keeps drawing near to his Lord through supererogatory acts and obligations until he attains the love of Allah. When Allah loves him, He rightly guides his following four organs:
He rightly guides him in his hearing, thus, he hears nothing but what pleases Allah.
He rightly guides his eyes. Thus, he looks at nothing except what Allah loves to look at and what pleases Him.
He rightly guides his hands. Thus, he does nothing with his hand except what pleases Allah.
He rightly guides his feet. Thus, he walks to nothing except what pleases Allah and pursues only what is good.
Along with all this, if he asks Allah for something, He grants him his request, and his supplication will be answered; and if he seeks refuge with Allah and resorts to Him seeking protection, Allah Almighty will grant him refuge and protection against what he fears.
Then, Allah Almighty says: I do not hesitate to do anything as I hesitate to take the soul of the believer out of mercy for him because he hates death, given the pain it involves, and Allah hates what hurts the believer.