This is what many elders in my church teach. They suppose that "Sell that ye have and give to the poor" was a commandment given exclusively to the rich young man. Of course they have to explain away why they themselves don't obey this commandment. But, ... take a look at the following verses:
Luke 12:33 King James Version (KJV)
33 Sell that ye have, and give alms; (there is no rich man here).
Acts 2:45 King James Version (KJV)
45 And sold their possessions and goods, and parted them to all men, as every man had need.
note: The Dispensation of Grace didn't come into effect right after the crucifixion -- there was a long transition period. In Acts 2:45 the disciples were still obeying Jesus' commandment.
The preceding verses in Acts 1 and 2 show that many people had traveled to Jerusalem from
various far-flung locations in the region. They had journeyed there to keep the annual Pentecost
convocation. As Christ’s disciples assembled in the temple for the observance, the Holy Spirit
came and filled them. Peter then delivered a Pentecost message, and some 3,000 people—
including many of those visiting from outside of the city—were converted and baptized into
the Christian faith. This marked the beginning of the New Testament Church.
These new converts were overjoyed to learn the truth of God, and many decided to stay in
Jerusalem longer than originally planned to learn more from the apostles and other members.
As a result, they ran out of funds and food, and were in need of help.
Consequently, of necessity, they formed a sort of community for the time being only. And whenever
some in poorer circumstances had need because of these unexpected conditions, others in better
circumstances would from time to time sell part of their goods or land and share with the less fortunate.
These early Christians were not practicing communism. They were responding to the needs of a
temporary and extraordinary situation. And they were responding to those needs with voluntary
generosity and compassion.
The Bible also shows that not all of the Church members sold their private property for this emergency.
Only some of them chose to—and only on a voluntary basis. This is clear from a conversation Peter had
with a member named Ananias who had sold some of his property. “The property was yours to sell or not
sell, as you wished,” Peter said to him. “And after selling it, the money was also yours to give away”
It is clear that Ananias—like all of these individuals—privately owned his property and could do
with it as he chose. “Here was private enterprise, and private initiative, and private ownership
—not regimented communism.
After the new converts left Jerusalem to return to their homes, this temporary “all things common”
situation ended. It is true that generosity, compassion and giving remained a central Church practice
(e.g. Acts 11:27-30; 20:35; 2 Corinthians 9:6-7; Galatians 2:10; 1 Timothy 5). But such instances of
giving were carried out by Church members only on a voluntary basis, and not at all in line with the
Communist model of state-mandated redistribution of wealth.