The angel answered, "The Holy Spirit will come on you, and the power of the Most High will overshadow you. So the holy one to be born will be called the Son of God. Luke 1:35 

The two phrases in this verse - "come on you" and "overshadow you" - tell an amazing story. 

The phrase "come on you" is the Greek word epercomai (ἐπέρχομαι) which means to come upon, come to, arrive, come on. But more than just arriving, what comes upon "comes and leaves its appropriate, inevitable effects that build on the particular coming. (Note the prefix epi, showing the action as the 'epi-center' of what happens.)"i 

"Overshadow you" is the word episkiazó (ἐπισκιάζω) which means overshadow, envelop, to cast a shadow on, and leave "a natural (apt) result." The word is "used in the NT of God's over-shadowing presence – which always brings His boulē-plan to pass." God's boulḗ is "God's immutable will for physical circumstances." 

God's coming causes something to happen! His coming upon and overshadowing of Mary was the epicenter of a history-splitting event, an inevitable effect, the natural result of the Most High God touching His creation and bringing His plan and purpose to pass. And the writer of Hebrews says that this plan and purpose of God is unchanging. 

Because God wanted to make the unchanging nature of his purpose (boulḗ) very clear to the heirs of what was promised, he confirmed it with an oath. Hebrews 6:17 

When God overshadows something or someone His unchangeable, immutable, unalterable purpose is accomplished. This overshadowing, purposeful, building Presence calls to mind Genesis. In the beginning God overshadowed, hovered over, the world to accomplish this purpose. 

Now the earth was formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters. Genesis 1:2 

What was God's original plan and purpose? To have relationship; to have sons and daughters to communicate Himself to and to love. And so, He created the first man and woman, Adam and Eve. They were unfaithful to Him and rejected Him. But His purpose remained unchanged. So just as God hovered over the earth in the beginning and created the first Adam, he hovered over Mary to create the last Adam, Jesus Christ Son of God, who would bring God's boulē-plan to pass. 

So it is written: "The first man Adam became a living being"; the last Adam, a life-giving spirit. 1 Corinthians 15:45 

In him we have redemption through his blood, the forgiveness of sins, in accordance with the riches of God's grace that he lavished on us. With all wisdom and understanding, he made known to us the mystery of his will according to his good pleasure, which he purposed in Christ, to be put into effect when the times reach their fulfillment—to bring unity to all things in heaven and on earth under Christ. Ephesians 1:7-10 

For I have come down from heaven, not to do my own will but the will of him who sent me. And this is the will of him who sent me, that I should lose nothing of all that he has given me, but raise it up on the last day. For this is the will of my Father, that everyone who looks on the Son and believes in him should have eternal life, and I will raise him up on the last day. John 6:38-40 (ESV) 

"The Lord was never a passive or unconcerned God; rather, He was always actively intervening, even invading the affairs of men. His incarnation as one of us is the most spectacular example of the Lord's lovesick and purposeful involvement in the earthly realm." -- Jill Shannon, A Prophetic Calendar 

Do you see how one-track God is? His purpose has always been to love us and to be loved back. And if we cooperate by turning towards Him, with even the feeblest opening of our hearts, He is there. When we crawl under the shadow of His wings, and let God overshadow us; when we hide ourselves in and cling to Him, then we put ourselves at the epicenter of His life-giving and creating and redeeming power. We allow Him to complete His passionate purpose in our lives. And nothing can come between us and God's passionate, one-track, love and purpose for us. No matter the circumstance. No matter the storm. No matter the attack of the enemy. No matter even our own rebellious, struggling, wavering hearts - for even a faintly burning wick he will not snuff out (Isaiah 42: 3). God will fulfill His purpose for us. 

Be merciful to me, O God, be merciful to me, for in you my soul takes refuge; in the shadow of your wings I will take refuge, till the storms of destruction pass by. I cry out to God Most High, to God who fulfills his purpose for me. Psalm 57:1-2 (ESV) 

And I am sure of this, that he who began a good work in you will bring it to completion at the day of Jesus Christ. Philippians 1:6 (ESV) 

So now I live with the confidence that there is nothing in the universe with the power to separate us from God's love. I'm convinced that his love will triumph over death, life's troubles, fallen angels, or dark rulers in the heavens. There is nothing in our present or future circumstances that can weaken his love. There is no power above us or beneath us—no power that could ever be found in the universe that can distance us from God's passionate love, which is lavished upon us through our Lord Jesus, the Anointed One! Romans 8:38-39 (The Passion Translation) 

iAll definitions from HELPS Word-studies, Discovery Bible (2021), and Strong's Exhaustive Concordance of the Bible. 

Image copyright by Derek Bair