Hashem appeared to Avraham and then Avraham looked up and saw three men walking and he ran to them from the entrance and he said please wait He brought water for them so he can wash there feet  and let them recline under the tree. Avraham said i will go get some bread (food) then the three people said "Do so Just as you have said"Avraham told to Sarah three meals,fine flour, make cakes.

              

            Avraham gave these three people a nice good calf and took milk and gave it to them. Avraham was standing next to them and watched them eat the food

    Later on these people where really angles that Hashem had sent and there names are Gabriel,Michael,and Rephael.

    Gabriel was sent to destroy Sedom

        Michael was sent to cure Avraham

           Rephael was sent to say that Sarah will have a baby boy in One year