Hadith: Indeed, when Allah loves a slave, He calls Jibrīl (Gabriel) and says: I love so-and-so, so love him. So, Gabriel loves him

عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ عَنِ النَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَالَ:
«إِنَّ اللهَ إِذَا أَحَبَّ عَبْدًا دَعَا جِبْرِيلَ فَقَالَ: إِنِّي أُحِبُّ فُلَانًا فَأَحِبَّهُ، قَالَ: فَيُحِبُّهُ جِبْرِيلُ، ثُمَّ يُنَادِي فِي السَّمَاءِ فَيَقُولُ: إِنَّ اللهَ يُحِبُّ فُلَانًا فَأَحِبُّوهُ، فَيُحِبُّهُ أَهْلُ السَّمَاءِ، قَالَ ثُمَّ يُوضَعُ لَهُ الْقَبُولُ فِي الْأَرْضِ، وَإِذَا أَبْغَضَ عَبْدًا دَعَا جِبْرِيلَ فَيَقُولُ: إِنِّي أُبْغِضُ فُلَانًا فَأَبْغِضْهُ، قَالَ فَيُبْغِضُهُ جِبْرِيلُ، ثُمَّ يُنَادِي فِي أَهْلِ السَّمَاءِ إِنَّ اللهَ يُبْغِضُ فُلَانًا فَأَبْغِضُوهُ، قَالَ: فَيُبْغِضُونَهُ، ثُمَّ تُوضَعُ لَهُ الْبَغْضَاءُ فِي الْأَرْضِ».
[صحيح] - [صحيح مسلم] - [صحيح مسلم: 2637]

Abu Hurayrah (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said:
"Indeed, when Allah loves a slave, He calls Jibrīl (Gabriel) and says: I love so-and-so, so love him. So, Gabriel loves him. Then, he (Gabriel) calls out in heaven, saying: Indeed, Allah loves so-and-so, so love him. And the inhabitants of heaven love him. Then, acceptance is established for him on earth. And if Allah hates a slave, He calls Gabriel and says: I hate so-and-so, so hate him. So, Gabriel hates him. Then, Gabriel calls out to the inhabitants of heaven, saying: Indeed, Allah hates so-and-so, so hate him. So, they hate him, and hatred is established for him on earth."
[Authentic hadith] - [Narrated by Bukhari & Muslim] - [Sahih Muslim - 2637]

Explanation

The Prophet (may Allah's peace and blessings be upon him) informed that when Allah loves His believing slave who obeys His commands and avoids His prohibitions, He calls Gabriel: Allah Almighty loves so-and-so, so love him. Then Gabriel, the master of the angels (peace be upon him), loves him and he calls the angels in heaven: Indeed, your Lord loves so-and-so, so love him. So the inhabitants of heaven love him, and acceptance is established for him in the believers' hearts that feel love, inclination, and contentment toward him. When Allah hates a slave, He calls Gabriel: I hate so-and-so, so hate him, and Gabriel; thus, hates him. Then Gabriel calls the inhabitants of heaven: Indeed, your Lord hates so-and-so, so hate him and they hate him. Then hatred and abhorrence are established for him in the believers' hearts.

Benefits from the Hadith

1. Abu Muhammad ibn Abi Jamrah said: Giving that command to Gabriel before other angels demonstrates his high rank and esteemed status with Allah Almighty above the rest of the angels.
2. Whomever Allah loves is loved by the inhabitants of heaven and earth, and whomever Allah hates is hated by the inhabitants of heaven and earth.
3. As-Sindi said: His statement (then, acceptance is established for him on earth) does not necessarily imply general or universal acceptance, but rather it is in accordance with the amount of acceptance Allah wills for him on earth, especially considering that the enmity of the wicked toward the righteous is well known.
4. Encouragement to fulfill all types of righteous deeds—both obligatory and supererogatory—and a warning against sins and innovations, as they are likely causes of Allah's displeasure.
5. Ibn Hajar said: From this, it is understood that the love of people's hearts is a sign of Allah's love, and this is supported by what is mentioned regarding funerals: "You are Allah's witnesses on earth."
6. Ibn al-‘Arabi al-Māliki said: What is meant by "the inhabitants of earth" are only those who know him, not those who do not know him and have never heard of him.