Section 147 is the supplement to Section 146. When any question relating to a matter relevant to the suit or proceeding is put to the witness, the provision of Section 132 shall apply. Under section 132 a witness cannot be excused from answering any question relevant to the matter in issue on the ground that answer to such question may criminate him or expose him to penalty or forfeiture. Thus, the court can compel a witness to answer to the relevant question. When such question is relevant which affects the credit of witness the court is to decide the matter under section 148 whether he shall be compelled to answer or not.