Kitab-i-Iqan — Paragraph 21

Afterwards, the companions and disciples of Jesus asked Him concerning those signs that must needs signalize the return of His manifestation. When, they asked, shall these things be? Several times they questioned that peerless Beauty, and, every time He made reply, He set forth a special sign that should herald the advent of the promised Dispensation. To this testify the records of the four Gospels.