'Spirits' in the Bible

And he says of the angels, "He makes his angels spirits and his ministers a flame of fire,"

Are they not all ministering spirits, sent out to serve those who will inherit salvation?

Besides, we have experienced discipline from our earthly fathers and we respected them; shall we not submit ourselves all the more to the Father of spirits and receive life?

and congregation of the firstborn, who are enrolled in heaven, and to God, the judge of all, and to the spirits of the righteous, who have been made perfect,