The O Antiphon for today is found in the Gospel Acclamation:
"O Leader of the House of Israel,
giver of the Law to Moses on Sinai:
come to rescue us with your mighty power."
All the Aniphons give the Lord special titles and all ask Him to come.
This is the final week of Advent and we are to prepare our hearts by desiring the Lord of all to come again. We need Him.