Acts 9:22 But Saul increased all the more in strength, and confounded the Jews who dwelt in Damascus, proving that this Jesus is the Christ.
When God asks you to do something, believe Him and believe in Him to give you the strength and words to say.
Saul was recognised wherever he went as the one who had done so much against Christians, and yet now Christ was filling him with the right stuff to prove others wrong in their assumptions.
Trusting in Christ does not just mean saying you do but really putting your life in His hands for everything!