"Celebrate with a sacred assembly"
One point that is repeated in this reading is the important of celebrating "with a sacred assembly." This reminds us that the worship of God is not meant to be an entirely individualistic activity: we must gather together. That is why we have Church: as an entity and an activity.
Another point that is repeated is not doing work on the days of celebration. Sadly, this concept has been largely destroyed in the modern world. Sundays and holidays are bigger days of work than ever for many.
No matter what our work obligations may be, however, a key aspect that must be retained in the importance of focus during time of sacred celebration: not just keeping "Christ in Christmas" or going to Church on Thanksgiving, but even when we are at Church to keep our focus on the Word and the worship of God, rather than the social and aesthetical elements of our gatherings.
Come, let us worship the Lord.