According to Bultman, Greeks did not see any reason to be grateful for their existence (see Bultman’s essay, “God and Man in the Old Testament”, Existence and Faith: Shorter Writings of Rudolf Bultman). There is truth in this statement, and there is also error. More precisely: the earlier Greeks did not see any reason to be grateful for their existence. By earlier I mean before Plato.
In Plato there is expressed a different tradition, having its start to the orphic teachings and the understanding that life in the other world was not just a shadow and caricature of this life, but a continuation, even more intense and real than this life.
Thus, earlier Greeks were not feeling grateful, because they recognised a vast presence of death undermining their existence. Their sense of humility meant rather their ‘obligation’ to exist according to a measure that rules over everything, even over the gods. It was an ontological principle rather than a moral one.
We can understand this clearly, if we just recall Plato’s Phaedo and Socrates’ reasons why a man should not commit suicide, even when leaving this life becomes something desirable.
In that speech gods appear particularly and devotedly caring for people. Plato’s emphasis in one’s personal character as the only property that is maintained in the other life, (in Theaetetus and elsewhere), as well as the notion of a God that is devoted to bringing man to the highest possible likeness with Him, (in Timaeus and elsewhere) were reasons for being grateful, simultaneously recognizing that being ungrateful, i.e. ignorant of God’s great care for men, is the gravest sin.
Yet, even with and after Plato, the general mentality of the Greeks did not change, which makes Bultman’s observation even more true. The turn that was expressed mainly with Plato did not have a popular / religious / mythical expression – the ancient gods were being abandoned, but there had not appeared yet their replacement – since, of course, Plato’s Creator was just that, it was Plato’s and it influenced mainly a circle around Plato,