The closest people to Allah are the ones who give the Salām first
Authentic hadithعن أبي أمامة رضي الله عنه قال: قال رسول الله صلى الله عليه وسلم : «إن أَوْلَى الناس بالله من بَدَأَهُمْ بالسلام». وفي رواية للترمذي: قيل: يا رسول الله، الرَّجُلان يَلْتَقِيَان أَيُّهُمَا يَبْدَأُ بالسلام؟، قال: «أَوْلاهُمَا بالله تعالى».
Abu Umāmah (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "The closest people to Allah are the ones who give the Salām first" [Abu Dāwud]. In the narration of At-Tirmidhi: The Messenger of Allah (may Allah's peace and blessings be upon him) was asked: "When two persons meet, who should give the Salām first?" He said: "The one who is closer to Allah."
Explanation
The best of people and those who are the most obedient to Allah are the ones who hasten to greet their brothers with Salām (saying: As-Salāmu ‘alaykum). This is because he hastens to do an act of obedience to Allah, seeking Allah's reward. This is what makes him closest to Allah and most obedient to Him.
Source · Narrated by At-Termedhy - Narrated by Abu Daoud
From the Hadith Encyclopedia (hadeethenc.com).