Thou art waxen fat, thou art grown thick, thou art covered with fatness.

-Bible (Old Testament)
Deuteronomy 32:15.

The advantage of doing one's praising for oneself is that one can lay it on so thick and exactly in the right places.

-Butler, Samuel
  The Way of  All Flesh, ch.34.

I'm as thick as a plank.

-Diana, Princess of Wales
Remark quoted in Sunday Today, 25  Jan1987.

Doeg, though without knowing how or why, Made still a blund'ring kind of melody; Spurred boldly on, and dashed through thick and thin, Through sense and nonsense, never out nor in; Free from all meaning, whether good or bad, And in one word, heroically mad.

-Dryden,John
Absalom and  Achitophel, pt.2, l.412^17.