The Hellenes believed that their group's widows had a moral claim on the funds, even though they did not have a legal claim. This was not an insurance contract, yet the system functioned analogously to such a contract. The apostles' implied arrangement was not a legal contract. A moral claim is difficult to define and describe, which is one reason why moral claims are not formally agreed to in advance by participants in an institution. Written contracts do not apply well to cases governed by moral criteria.
Acceptable performance is difficult to specify.
A theory of an implied contract may be offered retroactively to justify moral claims to scarce resources. The terms of implied contracts are vague or highly complex. The moral principles that supposedly govern these implied contracts may be disputed. This is why disputes over moral claims to scarce economic resources are not easily settled to the satisfaction of all those who make these claims. The murmuring began because there was no way for the Hellenes to establish a legal claim to church funds on behalf of their subgroup's widows.