There were originally 15 occurrences of the archaic infinitival form for to in the original text. This construction is found quite frequently in the King James Bible, as in “and all countries came into Egypt to Joseph for to buy corn” (Genesis 41:57) and “but all their works they do for to be seen of men” (Matthew 23:5).
In the editing for the second (1837) edition of the Book of Mormon, 13 instances of for to were removed by deleting the for; nine of these deletions were marked by Joseph Smith in the printer’s manuscript. But two instances of for to were left unedited: namely, in Mosiah 13:25 and Alma 12:4, both of which have remained in the text (see the discussion under Mosiah 13:25). For a list of all 15 instances, see for to in volume 3. The critical text will, of course, restore all 13 original occurrences of for to that were removed in the editing for the 1837 edition.
Summary: Maintain all 15 original instances of for to in the text, as in Mosiah 20:1 (“for to sing”).