While Luke 1:28 supports the doctrine of Mary’s Immaculate Conception,
there are many other solid arguments for believing in it.
It is very fitting that in one person, Mary, God has completely triumphed over Satan. In her, by God’s grace, Satan was completely rebuffed from beginning to end. The rest of us have sinned and have been under the domain of Satan, till we were baptized.
This doctrine of the Immaculate Conception can be found in what God says to Satan in
Genesis 3:14-15
“And the LORD God said unto the serpent … I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.” KJV
Identity of the Woman
All Christians agree that this is a prophecy about the Messiah, Jesus Christ, coming to strike the head of the serpent, Satan. - Actually the Hebrew word that is translated as “seed” is being used in a very unusual way. Normally it applies to the male, but here it is being used in reference to a woman. It is referring to Jesus’ birth through the Virgin Mary. - So, looking back at this Scripture we should appropriately ask ourselves, of which woman’s seed was He born ? The answer of course is Mary. Jesus even goes on to identify Mary as the “Woman” in John 2:4 , 19:26, and also see Revelation 12: 1, 5.
It is important to note that the creation of the enmity between Satan and the woman is not something that the woman does, rather it is what God does, and He does it in the most perfect way. Unfortunately some Christians in their misguided attempts to defend the glory of God actually insult Him by denying Him the credit that is due for this miraculous work He did in Mary.
Enmity is a determined, enduring and extreme hostility that exists between enemies.
Every Christian once in heaven will be perfected by God’s grace. However, only of Mary, and of “her seed,” which is Jesus Christ, is it said that there will be enmity between them and Satan. Since Jesus is God and since holiness is an aspect of His Nature, he has that enmity by nature. Where as with Mary, she has it as a gift.
If there had ever been a time when Mary was under Satan’s domination through personal or original sin, then there would not be a real enmity between her and Satan. Therefore, by virtue of the grace He gave her, God put Mary in opposition to Satan from the beginning and throughout her life. Notice that God the Father says that
He will put the enmity between her and Satan. Only in God, and by His gift of grace, also in Mary, can it be said that there is enmity with Satan because only in them is their entire life opposed to Satan.
Therefore, since Mary had an enmity between her and Satan, and even though she was a descendant of Adam and would have contracted Original Sin, she was saved from the stain of it by the merits of Jesus Christ from the first moment of her life.
https://www.defendingthebride.com/ma2/conception.html
I hope this helps,
John