Musannaf Ibn Abi Shaybah

Hazrat Asim and Hazrat Hammad both state, respectively, that Hazrat Ibn Sirin and Ibrahim, both of them, said: When you say, "Hayyak Allah" (May Allah give you life), then you should also offer Salam (greeting of peace) along with it.

Hazrat Abdul Hameed says that Hasan Basri considered it disliked to say: Hayyak Allah, unless he also said Salam.

Hazrat Muhammad bin Sawqah narrates: Hazrat Maymun bin Mehran came to us, so a man said to him: "Hayyak Allah" (May Allah keep you alive). He replied: Do not say it like this. This is the greeting of the youth. Rather, say: "Hayyakum Allahu bis-salam." (May Allah keep you alive with peace.)

Hazrat A’mash says that Ibrahim stated: The Companions liked that when a person said to another, “Hayyak Allah (May Allah give you life),” he should also say Salam along with it.