Hadith 42:30
Sahih (Al-Albani)
Jabir said, "When two people walking meet, then the one who gives the greeting first is the better of them."
قَالَ ابْنُ جُرَيْجٍ: فَأَخْبَرَنِي أَبُو الزُّبَيْرِ، أَنَّهُ سَمِعَ جَابِرًا يَقُولُ: الْمَاشِيَانِ إِذَا اجْتَمَعَا فَأَيُّهُمَا بَدَأَ بِالسَّلاَمِ فَهُوَ أَفْضَلُ
Original Reference: Al-Adab Al-Mufrad 994