Who was God dealing with throughout the Old Testament and up to this point in Acts?

God was dealing with His covenant people, the nation of Israel, throughout the Old Testament and up to this point in Acts. Scripture shows this program was directed not quite exclusively, but almost entirely to Israel, with some exceptions, until God began a new departure in His program for the human race.

Les explains that everything up to this point in time had been God dealing with His covenant people. Everything up through the Old Testament, as shown in the previous series of programs, was directed not quite exclusively, but almost entirely to the nation of Israel, though there were some exceptions. He notes that now there is a parting of the ways in God's program for the human race. For the first time, God is going to deviate from that whole concept of Jew only, and He will make this tremendous statement to Saul of Tarsus.

Acts 9:1

And Saul, yet breathing out threatenings and slaughter against the disciples of the Lord, went unto the high priest,

Who was God dealing with from the Old Testament through the early chapters of Acts?

From the Old Testament through Christ's earthly ministry and the early chapters of Acts, God was dealing with the nation of Israel under the Abrahamic covenant. Israel was God's earthly people, and their promises, Temple, and expectations were earthly rather than heavenly.