God works through you when you obey him. Often, just like Moses, we are insecure: will it all work out? When you do not obey the Lord, nothing will flow from your hands, but when you obey him, you will notice that God’s Word works.
Compare Philippians 1:5–6: Paul thanks God, because of your partnership in the gospel from the first day until now. And I am sure of this, that he who began a good work in you will bring it to completion at the day of Jesus Christ.
So, we see that the Philippians spread the gospel, and at the same time, it is God who works in them. God works through their obedience.
10 Moïse et Aaron allèrent auprès de Pharaon, et ils firent ce que l'Eternel avait ordonné. Aaron jeta sa verge devant Pharaon et devant ses serviteurs; et elle devint un serpent.