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 had become by all means a good. In that speech gods appear particularly and devotedly caring for people. Plato’s emphasis in personal character as the only property that a man takes with him 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 good enough to make some feel grateful, simultaneously feeling man’s being ungrateful, i.e. ignorant of God’s great care for men, as the gravest sin.
Yet, even with and after Plato, the situation did not change in general, which makes Bultman’s observation even more true. The shift in the view of existence 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, Plato’s and a circle’s around Plato, He did not belong to a faith and tradition of the city. This is also the reason why Paul placed so much emphasis in the victory against death, when he spoke in Athens.
Jews, on the other hand, were grateful for their existence, yet recognising in God the source of their goods, thus valuing the creations and donations of God more than God himself. This explains also why there was not in their religious life the notion of “becoming like God”, the dominant notion in (the Orthodox) Christianity – even in Plato.