What did muhammad first revelation instruct all muslims to do?

Muhammad's first revelation was the event in which Muhammad was visited by the archangel Gabriel in 610 CE, who revealed to him a verse from the Quran. It instructed them to praise only Allah and follow the footsteps of Muhammed.

Monday 4 December 1916
My dear little Marjorie,
I have only just received your little letter which Mamma sent with hers on Nov 19th. Do you remember that you asked me to be home for Xmas? I only wish I could but there are many more soldiers in our Battery who are more entitled to the Xmas leave than I am, so I’m afraid you will have to do without Daddy this Xmas. Santa Claus will come as usual.
I think your writing and dictation just splendid, and your drawings are getting funnier than ever. I have pinned your crayoned tulips on the wall of my dug-out bedroom beside your photograph.
Daddy is as comfortable as possible. I expect even you would get tired enough to go soundly asleep in this dug-out. It would be a change from your pink bedroom. And how is little Daffodil getting on? I expect you quite enjoy the time when Mamma reads you more about her. It was Mamma’s book when she was a girl like you. Write again soon, dear, + send another crayoning to help cover the sand bags.
Heaps of love & kisses, which you must share with Mamma and Betty.
From your ever loving Daddy