# he will be great in the sight of the Lord

"he will be a very important person for the Lord" or "God will consider him to be very important"

# he will be filled with the Holy Spirit

"he will be full of the Holy Spirit" or "the Holy Spirit will empower him" or "the Holy Spirit will guide him"

# from his mother's womb

"even while he is in his mother's womb" or "even before he is born"