The Holy Spirit will come upon you, and the power of the Most High will overshadow you. - Luke 1:35, NIV
When the angel Gabriel appeared to Mary, he gave her the startling announcement that “the Holy Spirit will come upon 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.” When you and I place our faith in Jesus Christ and invite Him to come live within us, the Holy Spirit comes upon us, and the power of God overshadows us, and the life of Jesus is born within us. We do not conceive a physical life, but the spiritual life of Jesus in the Person of the Holy Spirit.
It is the indwelling powerful Person of the Holy Spirit Who sets me free from the habits of sin. But the power I possess to live a life pleasing to God is directly related to how much control of my life I give to the Holy Spirit.
From Just Give Me Jesus