Acts 13:47

“For so has the Lord commanded us, saying, ‘I have set you for a light of the Gentiles, that you should be for salvation to the uttermost part of the earth.'

And they were comforted by this one fact. That this was what the Lord had commanded them in the Scriptures. For He had declared to His Servant ‘I have set you for a light of the Gentiles, that you should be for salvation to the uttermost part of the earth' (Isaiah 49:6). Thus by their action in bringing light to these darkened hearts they were demonstrating their oneness with the Servant of God Who had come, and were aligning themselves with Him in His task of bringing them salvation, a task which also became theirs, because by being united with Him they too had become God's Servant.