Although a forfeiture of good time will not bar a prisoner from receiving a parole hearing, D.C. Code 24-404 permits the Commission to parole only those prisoners who have substantially observed the rules of the institution. Consequently, the Commission will consider a grant of parole for a prisoner with forfeited good time only after a thorough review of the circumstances underlying the disciplinary infraction(s). The Commission must be satisfied that the prisoner has served a period of imprisonment sufficient to outweigh the seriousness of the prisoner's misconduct.