Together was clearly a byproduct of the outpouring of the Holy Spirit (especially as the church began to grow). The joyful expressions of together in the New Testament accounts were Spirit-inspired and spontaneous.
While together was inspired by the Holy Spirit, it is not a passive word. It begins with conscious participation - a decision to "be" together. Together is a choice.
We long for this kind of connection. We are made for it. And it is still available. We need a fresh outpouring of the Spirit, and then obedience to His prompting. We are better together.
Living life "to the full" or "abundantly" is enhanced because we do life together.