1 Samuel 9:6

And he said unto him, Behold now, there is in this city a man of God, and he is an honourable man; all that he saith cometh surely to pass: now let us go thither; peradventure he can shew us our way that we should go.

Cross-references

1 Samuel 3:19 says none of Samuel's words fell to the ground, directly confirming the servant's claim that all he says comes true.

1 Samuel 3:20 states all Israel knew Samuel was a prophet, explaining why the servant would trust his words.