Why was it necessary for the Holy Spirit to be at work in the life and ministry of Christ from the virgin conception to his resurrection from the dead, and how is the Spirit at work in the lives of believers?

Why is it that no one can inherit eternal life without being regenerated by the Holy Spirit, and why is this truth a comfort for believers?

Both the Spirit and the Son are called intercessors—they are nonexpendable in the work of our intercession (or prayer). And this by necessity requires the Father, too. How does knowledge of the Trinity strengthen our prayer life?