Personal pronouns are often left out since they are implied. When the first or second person pronoun does occur, it denotes emphasis.
ερχομαι επι την οικιαν
εγω ερχομαι επι την οικιαν
Note: both “ερχομαι” and “εγω ερχομαι” mean I come. The pronoun is implied in the former and explicit in the latter. The only difference between the two is a greater emphasis on εγω when it is explicit. cf. BBG 16.15.