They are not the same words in original languages. The OT (Hebrew) uses the word chaciyd which translates as faithful, kind (hardly a 'saint'). The Hebrew word for 'saint' is qadowsh (holy one).
The OT Greek version (LXX) uses όσιος (hosios) without blame, pious..
the New Testament uses exclusively the word άιγιος (haigios), or most holy
Clearly the Hebrews in the OT do not refer to all the faithful as "saints" (i.e. holy ones), whether in Hebrew or Greek. That is a Pauline innovation which the Church never accepted.
The Lutherans went one step farther and called themselves the divines!. Talk about narcissism.
I don't have my Hebrew lexicon handy at the moment, so I'm not sure how often "chaciyd" versus "qadowsh" is used. However the term qadowsh (holy one) is used in a plural sense:
Psa 34:9 O fear the LORD, ye his saints: [sic: qadowsh] for [there is] no want to them that fear him.
What the Lutherans called them is immaterial. I'm not Lutheran.