A house built on sand

When I wanted to include in yesterday's post on Autosuggestion an ironic allusion, I googled on jesus house built on the sand for the precise gospel source, and the very first item on Google's list (of 341,000 items) was "A house built on sand - Testimonies of Ex-Christians," a coincidentally corroborating post from M in Helsinki (December 11, 2003):

Jesus teaches in the Sermon on the Mount to build the houses of our faith on the solid rock of his teachings (Mt 7:24-27). Too bad that the religion based on his teachings is a house built on sand. [emphasis mine] However strong you make the internal structure of your faith, there is no external rock that it is anchored to. So when the flood of rational thinking hits it, it will fail.
    My parents became born again Christians when I was 5. They started in Pentecostal and Lutheran circles, but soon ended in charismatic and Word of Faith (you know, the name-it-and-claim-it bunch, e.g. Hagin, Copeland, Oral Roberts) connections, though there were no such churches in the area we lived. As the only child I grew up with the faith, starting to speak in tongues at 7 and getting baptized at 14.
    ...[skipping to M's concluding sentence:] It just happens that the rock is reason and the sand Christianity.

That final sentence of course expresses my own affiliation with reason rather than blind faith in primitive doctrines. However, the "internal structure" of these doctrines is decidedly not strong, however much apologists over the years have tried to shore up the doctrines. I take exception with M on that. But he may well have revised this opinion, expressed as it was before the appearance of the books of Sam Harris, Christopher Hitchens, and Richard Dawkins that I occasionally cite here to elaborate various problems of religion.