The Bible is by far the very best source of copywork and dictation material for children.
I have mentioned before, that one of the things I would change if I could go back and redo our homeschooling years, is to include more Bible copying and dictation, and less literature. Literature is valuable, but the Bible is the most valuable literature your children can practice.
You could have your children copy straight from the family Bible. If the print is too small for young eyes, however, make your own copywork pages from your computer. Valuable copywork workbooks do exist, however, such as the new Proverbs Copywork Workbook by Katherine Hirn, so that you don’t need to repeat the labor others have already done.
Here and there also add in hymns, poetry, literature and orations, and the quotes of the wise.