1 Samuel 3:19-20

3:19 Samuel continued to grow, and the Lord was with him. None of his prophecies fell to the ground unfulfilled. 3:20 All Israel from Dan to Beer Sheba realized that Samuel was confirmed as a prophet of the Lord.

Jeremiah 28:9

28:9 So if a prophet prophesied peace and prosperity, it was only known that the Lord truly sent him when what he prophesied came true.”