Origen

“ But the number of believers is small who belong to Israel according to the flesh; one might venture to assert that they would not nearly make up the number of a hundred and forty-four thousand. It is clear, therefore, that the hundred and forty-four thousand who have not defiled themselves with women must be made up of those who have come to the divine word out of the Gentile world. In this way the truth of the statement may be upheld that the first fruits of each tribe are its virgins. For the passage goes on: “These were brought from among men to be a first fruits to God and to the Lamb ”