Well ... it's voluntary in the sense that you can decide not to live by biblical standards.
But no, the mosaic Law system and the Christian community were not just regular systems that allowed individual voluntary philanthropy, they were actual COMMUNAL and Social justice based econoimc systems.
And yes, there is something in the bible suggesting it's not right and good, InFact in the mosaic Law Usury is illigal, which is the Foundation of Capitalism, and God Condemned a Society (not individuals) for not taking care of the poor, meaning God considers it a communal and societal obligation, which is why the jubilee, sabattical, gleaning, anti-usury laws and other LEGAL systemic institutions were in the mosaic Law code and why the first Century CHristian community didn't just practice philanthropy, they actually set up a communal economic system.
Life Liberty and the Pursuit of Happiness is a secular mantra ... it's not in the bible.
The bible Calls for justice and righteousness.
The social Gospel is, and always has been part of the gospel, People leave when the rest of the gospel is left out.
I did not say there is no social gospel in the Bible. Of course there is both in the Old and New Testaments. But again, charity as expressed in Biblical doctrine is voluntary, not mandatory and justice is commanded by God and not a dictate of government. The people organized the Church via social contract--voluntarily--not by decree. Yes, life, liberty, and pursuit of happiness are words from the Declaration of Independence, not the Bible, but they were hardly 'secular': ". . .“We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable rights, that among these are life, liberty and the pursuit of happiness.”. . .
And in my opinion they are supported by scripture:
“he said to them, 'Take to heart all the words I have solemnly declared to you this day, so that you may command your children to obey carefully all the words of this law. They are not just idle words for you—they are your life. By them you will live long in the land you are crossing the Jordan to possess.'”
Deuteronomy 32:46,47
“the man who looks intently into the perfect law that gives freedom, and continues to do this, not forgetting what he has heard, but doing it—he will be blessed in what he does.” (James 1:25).
“To the Jews who had believed him, Jesus said, 'If you hold to my teaching, you are really my disciples. Then you will know the truth, and the truth will set you free.'”
John 8:31,32
Galatians 5:13 - For, brethren, ye have been called unto liberty; only [use] not liberty for an occasion to the flesh, but by love serve one another.
Galatians 5:1 - Stand fast therefore in the liberty wherewith Christ hath made us free, and be not entangled again with the yoke of bondage.
Isaiah 61:1 - The Spirit of the Lord GOD [is] upon me; because the LORD hath anointed me to preach good tidings unto the meek; he hath sent me to bind up the brokenhearted, to proclaim liberty to the captives, and the opening of the prison to [them that are] bound;
2 Peter 2:19 - While they promise them liberty, they themselves are the servants of corruption: for of whom a man is overcome, of the same is he brought in bondage.
“if you obey my commands, you will remain in my love, just as I have obeyed my Father's commands and remain in his love. I have told you this so that my joy may be in you and that your joy may be complete.” (John 15:10,11)
There are many many more Biblical references for God's intention for humankind to live in a state of life, liberty, and joy. But absolutely no scriptures assigning the responsibility for that to either the Church or the government.