get (something) straight from the horse's mouth
To obtain information from the original or most reliable source. A: "Is our test really getting rescheduled?" B: "Yep, Mrs. Whitford told me. I got it straight from the horse's mouth!"
get something straight from the horse's mouth
Prov. to get information from the person most directly involved or best informed. Jill: Sue is going to have a baby. Jane: Who told you that? Jill: I got it straight from the horse's mouth. There's a rumor that Randolph is moving to Alaska, but I won't believe it until I get it straight from the horse's mouth.