What does it mean that God works both ends to the middle?
It means God simultaneously prepares and moves on two separate parties to bring about His purpose in the middle. While Saul was being confronted outside Damascus, God was also speaking to Ananias inside the city, arranging their meeting so His plan would be accomplished.
Les explains that God always works both ends to the middle. In Acts chapter 9, after Saul's experience on the road to Damascus, God was working on Saul outside the city while also working on Ananias in the city. God spoke to Ananias, a believing Jew somewhere in Damascus, telling him to arise, go into the street called Straight, and inquire at the house of Judas for Saul, who was praying and had seen a vision of Ananias coming in. So God was preparing both men so their paths would meet and His purpose would be fulfilled.
And the Lord said unto him, Arise, and go into the street which is called Straight, and enquire in the house of Judas for one called Saul, of Tarsus: for, behold, he prayeth,