The phrase "Some of the scribes" likely does not refer to Sadducees, who would scarcely allow themselves to publicly commend the Lord for His astute reply. Instead, it is plausible that these individuals were Pharisees, who, despite having conspired against the Lord alongside the Sadducees, may have found satisfaction in witnessing their rivals brought to disgrace, as noted in Matthew 22:34 ff. Mark records that a scribe who questioned the Lord subsequently recognized the wisdom in His rebuttal to the Sadducees (Mark 12:23) and later voiced his approval (Mark 12:32).
It is possible that this particular scribe, alongside others who shared this perspective, approached the Lord after His response to the Sadducees, affirming, "Master, thou hast said well." The Lord’s adept use of Scripture to delineate the truth of the resurrection of the dead was so compelling that even His opponents honored Him on that occasion (Luke 20:40-44).
Furthermore, the Lord’s inquiry concerning the Messiah—regarding whose son He is—appears in an identical fashion in the Gospels of Matthew and Mark; see Matthew 22:41-46 and Mark 12:35-37. The phrase "They dared not ask Him" indicates that after the Sadducees were silenced, a scribe approached Him to inquire about the greatest commandment in the law (Matthew 22:35-40, Mark 12:28-34). Both Matthew and Mark note that subsequent to this discussion, no one dared to pose another question. Although Luke omits the dialogue concerning the greatest commandment, his assertion that they did not question the Lord stems from His own initiative to inquire about the identity of the Messiah, placing this dialogue right after His response regarding the resurrection.
The query "How then is He Son unto him?" is recorded, but Luke does not comment on the reaction of His audience to the Lord's question. This gap is filled by Matthew and Mark, with Matthew indicating that no one could respond to Him, and Mark asserting that the crowd was captivated by His teachings.