High Quality Content by WIKIPEDIA articles! The Common Sayings Source is one of many theories that attempts to provide insight into the Synoptic Problem. The theory posits that the Gospel of Thomas, a sayings gospel, and the Q source, a hypothetical sayings gospel, have a common source. Elements of this Common Sayings Source can be found in the text of the Gospel of Thomas and what scholars are proposing existed in the Q source. The high level of similarities between the two sources suggests that both documents are later redactions of a single source, the original Common Sayings Source, which was then redacted by different groups to suit their own needs.