A unit has the meaning of an individual thing or person regarded as single
and complete.
But just add another letter "Y" to that word and the meaning changes from being a individual to a united group.
In the 1st reading, the whole group of believers were united, heart and soul, and no one was in need as everything they owned was held in common.
That kind of unity is certainly not possible just by human determination or decision but by divine direction.
But still, mutual encouragement is necessary to keep that kind of unity as seen in the 1st reading.
Joseph Barnabas was one such example as he sold his property and presented it to the apostles.
But the unity was not just in earthly matters and mutual support.
The community was unity by a common love - the love of Jesus, and from that flows the love for one another.
May we love Jesus and love one another and united in the love of God, that will our testimony to the world of our faith.