Did Israel reject God while He was still dealing with them in the book of Acts?
Yes. The book of Acts shows God still dealing with Israel, while Israel was rejecting that dealing. As the rejection continued, God in effect said He would turn to the Gentile without them, and that is exactly what happened. This transition makes Acts significant.
Les explains that he loves teaching Acts because it reveals how God was still dealing with Israel, and Israel is rejecting it. Then God, in so many words, says, “Well, I’ll just turn to the Gentile without you.” That is exactly what happened, and it is what makes the book so exciting. At Acts chapter 8, the setting is still pretty much on Jewish ground; Stephen has just been stoned, and Saul of Tarsus was consenting unto his death.