To be bound together with someone, particularly in shared imprisonment. Hebrews 13:3 exhorts believers to 'remember those in prison as though bound together with them.' The identification goes beyond sympathy to solidarity—believers are to consider themselves co-prisoners with those suffering for the faith. The shared-binding imagery may be literal (some readers were fellow prisoners) or spiritual (all are vulnerable to persecution). Either way, it calls for empathetic action: visiting prisoners, providing for their needs, identifying with their suffering as one's own.