Yochanan I 2:3-6

3 And by this we have da’as that we have da’as of Him, if over the mitzvot of Him we are shomer.

4 The one making the claim, "I have da’as of Him" and not being shomer over His mitzvot is a shakran (liar) and in this one HaEmes is not.

5 But whoever over the dvar of Him is shomer, beemes in this one the ahavas Hashem has been made shleimah. By this we have da’as that in Him we are.

6 The one claiming to make his maon in Him ought with the halakhah of that One so he should have his derech. [Yn 14:1,23; TEHILLIM 1:6]