From Sahih Muslim (Hadith 5634):
Jabir b. Abdullah reported:I came to Allah's Apostle (ﷺ) and called him (with a view to seeking permission). whereupon Allah's Apostle (ﷺ) said: Who is it? I said: It is I. Thereupon he (the Holy Prophet) came out saying: It is I. it is I
Reference: Muslim 5634