Security attacks on time synchronization services prevent the Wireless Sensor Networks (WSNs) from operating consistently and possibly cause the system to go down entirely. One of the most vulnerable attack types where a node falsely assumes many identities is the Sybil attack. Despite receiving a lot of attention for their simplicity and distributed nature, consensus-based time synchronization (CTS) algorithms in WSN do not exhibit robust behavior when subjected to a Sybil attack. In this context, a message-level Sybil detection mechanism, the Sybil resilient consensus time synchronization protocol (SRCTS), is proposed using a graph-theoretic approach. A novel distributed mechanism based on connected component theory is proposed to detect and filter Sybil messages. The comparison has been shown with Robust and secure Time Synchronization Protocol (RTSP) and Node-identification-based secure time synchronization protocols (NiSTS) for detection and convergence speed. The Sybil message detection rate is improved by 6% as compared to SRCTS vs RTSP and by 14% as compared to SRCTS vs NiSTS. Simulation results exhibit that the SRCTS algorithm is 62% more effective as compared to NiSTS and 45% more efficient than RTSP in terms of convergence rate. An in-depth mathematical analysis is presented to prove the correctness of the algorithms, and the message complexity is proven to be O(n2). The algorithm is validated through extensive simulation results.