Luke had not told his readers that Jesus was anywhere near Peter. Perhaps Jesus was visible through a window, or His guards may have been leading Him past a place where He could see Peter. Luke"s unique reference to His turning and looking at Peter adds to the shock effect of the moment. The word that Luke used to describe Jesus" looking usually means to look with interest, love, or concern (Gr. emblepo). Peter suddenly remembered what Jesus had predicted earlier that evening ( Luke 22:34) and, undoubtedly, His profession of loyalty to Jesus ( Luke 22:33). The realization of his unfaithfulness in this light, along with Jesus" teaching on the importance of faithfulness, caused Peter to leave the courtyard and to weep tears of bitter remorse. [source][source][source]
Luke"s account of this outstanding disciple"s tragic failure stresses the importance of adequate spiritual preparation for times of testing. Like the other evangelists, Luke included this incident because of its timeless importance for all of Jesus" followers. [source][source][source]