A budget is a moral document, and reflects the values of its designers. But morality - as they say - is in the eye of the beholder and values always exist in a hierarchy, with some values being valued more than others. So the Coalition Government will crow about the righteousness of their budget, while their political opponents will denounce it as an assault on justice and fairness.

Over the last month since the budget was handed down, we've heard from religious-based charities, social service organizations and some of the more progressive denominations about its negative impact on the vulnerable and disempowered both here and overseas.

However, as a pastor credentialed by the Australian Christian Churches (formerly the Assemblies of God), I've been stunned by the relative silence from conservative Christian leaders and laypeople. Ordinarily, when something arises which is seen as a threat to Christian values or virtuous society, I receive an avalanche of emails requesting that I mobilise my congregation to action.

But in response to a budget that cuts billions from health and education while spending billions on new weapons of war; that targets pensioners, families, students, Indigenous Australians and other vulnerable groups for its savings and that will cost a single mother of a disabled child more than it will cost the most affluent Australian, there has been very little consideration of how people filling the pews of conservative Christian churches should respond theologically or politically. There has been no widespread call for society-saving action. My inbox is empty.

So where have all the Christians gone?

I can only assume this means either that we believe that the 2014 federal budget is a moral document in line with our values, or that we don't believe it's our role to say otherwise. It is perhaps most telling that, while there isn't widespread dismay about the national values reflected in the budget allocations, we have loudly praised funding for school chaplaincy. Could it be that the church is more worried about losing our government benefits than about Australia's most vulnerable losing theirs?

Or is there a less mercenary motivation for our silence? Perhaps we have determined that the budget is unrelated to Christian values. It is certainly not that we believe we shouldn't speak up when morality is threatened - the marriage equality and abortion debates make this abundantly clear. Instead, it would seem that we have concluded that conservative Christian sexual ethics, and our strangely inconsistent ethic of life, are the moral foundations of society - while loving our neighbour as ourselves and sacrificially preferring "the least of these" are lesser moral imperatives.

Indeed, if measured by the urgency and effort of our political engagement alone, our Christian value system might be summarised as: "It's fine if Australians live in poverty, as long as gay people can't get married."

There is much for us to gain by limiting our definition of morality in this way. Rather than reflecting on our complicity in a system of organized economic disadvantage, we are able to feel morally superior by committing ourselves to political causes that demand other people change their behaviour but that don't cost us anything.

Moreover, with demands for morality safely confined to the evil behaviour of others, we can then use our faith to validate our consumer lifestyle. We label our self-interest as "God's blessing" - blind to the fact that the blessing of God has become indistinguishable from the blessing of inherited privilege, or the blessing of tax minimisation.

It is perhaps a little too easy to join with the budget in measuring "cost" in economic, rather than social, terms. We can thus passively affirm the morality of a budget that places economic growth as its highest priority because it has become our own - and, we believe, with God's blessing.

But the Christian vision of "the good life" - as reflected in the words of Jesus and the writings of the New Testament - is informed by a moral vision that affords greatest honour to the least powerful, the most vulnerable, the perpetually excluded. It recognises that both the personal and public economies exist to serve the common good and that an "I earned it, I own it" philosophy stands opposed to the values of the one who told a man searching for the kingdom of heaven to "sell your possessions and give them to the poor."

We don't know how Jesus would have balanced the books if he were Treasurer. But we do know that individualism is the antithesis of a self-sacrificing Saviour, and that craven self-interest is the most un-Christ-like of motivations. We do know the scriptural injunction to "look out not only for our own interests, but also the interests of others." We know we have been called to "defend the cause of the poor and needy."

So - I find myself asking again - where have all the Christians gone?

Brad Chilcott is national director of Welcome to Australia and pastor of the Activate community in South Australia.