~During the years of revelation in Makkah, before Khadija RA's passing in 619 CE
During the years of revelation, Jibril would come to Muhammad ﷺ in Khadija RA's household, a privilege given to no other wife of the Prophet ﷺ. On one occasion, the Prophet ﷺ told Khadija RA that Jibril sent her Allah's salam and his own salam, along with glad tidings of a house in Jannah with no noise or struggling.
Illustrates Khadija RA's unique standing before Allah and her intelligence in how she received the greeting: naming Allah as al-Salam rather than returning the greeting to Him directly.
Other events recorded around the same time. Their order within the year is not established; use the storyline above for the sequence.
O Khadija, here is Jibril, and he is sending Allah's salam upon you, and he is giving you his salam, and is giving you the glad tidings of a house in Jannah where there will be no noise or any struggling.
Allah is al-Salam, and may salam be upon Jibril, and may salam be upon you, ya Rasulullah.