'Rock' in the Bible

he is like a [far-sighted, practical, and sensible] man building a house, who dug deep and laid a foundation on the rock; and when a flood occurred, the torrent burst against that house and yet could not shake it, because it had been securely built and founded on the rock.

And some seed fell on [shallow soil covering] the rocks, and as soon as it sprouted, it withered away, because it had no moisture.

Those on the rocky soil are the people who, when they hear, receive and welcome the word with joy; but these have no firmly grounded root. They believe for a while, and in time of trial and temptation they fall away [from Me and abandon their faith].