God's Long-Term Planning
Stephen was on trial for his life (Acts 6:12). But he was not concerned to defend himself; instead he wanted to explain who Jesus is - His arrival on earth was the apex of God's salvation plan. So Stephen described God's long-term planning starting with Abraham, Isaac and Jacob; then Moses and the wilderness experience, the tabernacle and the temple. But Israel's history was incomplete (indeed it could not really make sense) without Jesus (Acts 7:52-53).
God had told Abraham that although bad times would come, when His people would become slaves in Egypt, it was all part of His plan (Genesis 15:13-14). Justice would be done because God would punish the Egyptians for their cruelty to His people. Suffering would not last for ever because God's objective was to take them out (the exodus) so that they could worship in the Promised Land. The story of the Old Testament is a record of God's promises and the people's success or, much more often, failure in obeying His instructions.
Circumcision was a sign to remind them that God would certainly fulfil His long-term plan, and the people would be blessed if they trusted and obeyed (Genesis 17:1-14). All the male descendants from Abraham, Isaac and Jacob were marked with that sign. However, God's people failed in many ways; but God was not distracted from His plan for Jesus to be the one totally effective sacrifice for sins for ever (Hebrews 10:14). All the law could offer was punishment. Only Jesus could bring forgiveness and new life.
True worship can only come from forgiven people (Luke 7:41-43). Legalistic religionists may do their duty, but the Father seeks people who will worship from their hearts (John 4:23). The prelude to His plan, from Abraham to Jesus, took about two thousand years but Jesus still arrived on time. So do not be discouraged when it seems that God is taking too long to reveal His hand of power. He knows what He is doing now and is working everything together for the good of those who love Him. Most of all, remember that God's plan is centred on Jesus, not on you or your plans. As we seek His glory so we find our true purpose.