Ibn ‘Abbās (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said to Jibrīl: "What makes you not visit us more than you do?" Thereupon, the following verse was revealed: {And we [angels] descend not except by the order of your Lord. To Him belongs what is before us and what is behind us and what is in between.} [Maryam: 64]
This Hadīth indicates the Prophet’s longing for meeting Jibrīl (peace be upon him), who used to bring him the divine revelation. Jibrīl did not come to the Prophet (may Allah's peace and blessings be upon him) for forty days. So, he said to him: ''What makes you not visit us?'' i.e. it has been a long time since you last came, and I miss you. So, Allah revealed to Jibrīl to say to the Prophet: {And we [angels] descend not except by the order of your Lord. To Him belongs that before us and that behind us and what is in between. And never is your Lord forgetful.} According to this verse, revelation is sent down only with Allah's command and in accordance with His wisdom, for to Allah belong the affairs of the world and the Hereafter, and He never forgets anything. In other words, delaying the revelation does not mean that Allah has forgotten or left you. To conclude, this Hadīth suggests that one should accompany the righteous and visit them, for this is a good thing to do.