Sayyiduna al-Sa'ib bin Yazid (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) came upon some girls who were singing and saying: "You greet us and we greet you." The Messenger of Allah (peace and blessings be upon him) stopped, then called them and said: "Do not say this; rather say: May Allah keep us and you alive." A man said: O Messenger of Allah, do you permit people this? He (peace and blessings be upon him) said: "Yes, this is marriage, not fornication. Announce marriage."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6636