We did this last year with puff fabric paints and shaving cream to make colorful "stone tablets" on which we wrote the summary of the Ten Commandments known as the "Great Commandment." They turned out amazing and the kids loved it.
The trick: Before marbling, write your words in CRAYON before putting the paper "tablets" into the color-marbling shaving cream. The paint won't stick (as much) to the words. (write with thick lines of crayon wax).