tn The context of this statement in 1:6 indicates clearly that the progressive (continuative or durative) aspect of the present tense must be in view here.
sn The relationship of the phrase keep on walking to if we say is very important for understanding the problem expressed in 1:6. If one should say (εἴπωμεν, eipōmen) that he has fellowship with God, and yet continues walking (περιπατῶμεν, peripatōmen) in the darkness, then it follows (in the apodosis, the “then” clause) that he is lying and not practicing the truth.