This verb combines public proclamation with temporal priority—announcing something before it happens or before someone arrives. Classical usage included heralds proclaiming public notices or making advance announcements. In Acts 13:24, Luke describes John the Baptist's ministry as proclaiming beforehand (literally, 'having proclaimed before his coming') a baptism of repentance to all Israel. John's role was advance herald, the voice preparing the way, the announcer alerting Israel to ready themselves for the One coming after him.