Sayyiduna Muhammad bin Maslamah (may Allah be pleased with him) said: I passed by and saw the Messenger of Allah (peace and blessings be upon him) on al-Safa with a man, placing his cheek upon that man's cheek, so I went away. Not long after, the Messenger of Allah (peace and blessings be upon him) called me and said: "O Muhammad bin Maslamah! What prevented you from giving the greeting of peace?" Muhammad bin Maslamah (may Allah be pleased with him) said: O Messenger of Allah! I saw that you were doing something with this man that you have not done with anyone else, so I disliked interrupting your conversation. O Messenger of Allah! Who was he? He (peace and blessings be upon him) said: "That was Jibril (peace be upon him), and he said: 'What is the matter with Muhammad bin Maslamah that he did not give the greeting? Had he given the greeting, we would have returned his greeting.'" Muhammad bin Maslamah said: O Messenger of Allah! What did he say to you? He (peace and blessings be upon him) said: "He kept urging me so much regarding the neighbour that I began to think he would command me to make him an heir."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 16571