'Foundation' in the Bible

In discharge of the task which God graciously entrusted to me, I--like a competent master-builder--have laid a foundation, and others are building upon it. But let every one be careful how and what he builds.

For no one can lay any other foundation in addition to that which is already laid, namely Jesus Christ.

And whether the building which any one is erecting on that foundation be of gold or silver or costly stones, of timber or hay or straw--