Vincent's NT Word Studies
28. He followed (hkolouqei). Imperfect. He began to follow, and continued following.29-39. Compare Matt. ix. 10-17; Mark ii. 15-22.
Robertson's NT Word Studies
5:28 {He forsook all} (katalipwn panta). this detail in Luke alone. He left his profitable business for the service of Christ. {Followed him} (ekolouqei autwi). Imperfect active, perhaps inchoative. He began at once to follow him and he kept it up. Both #Mr 2:14; Mt 9:9 have the aorist (ekolouqesen), perhaps ingressive.