C.H. Dodd was one of the truly great NT scholars in the U.K. before, during and after WWII. His commentary on the Johannine Epistles is a classic, and continues to offer fresh insight into the text and its relevance for evaluating Christian life today. Here is a quote from that commentary that itself deserves both hearing and heeding:
"In this passage [I John 2.1-6] our author is not only rebutting dangerous tendencies in the Church of his time, but discussing a problem of perennial importance, that of the validity of religious experience. We may have the feeling of awareness of God, of union with Him, but how shall we know that such experience corresponds to reality? It is clear that no amount of clearness or strength in the experience itself can guarantee its validity, any more than the extreme vividness of a dream leads us to suppose that it is anything but a dream. If, however, we accept the revelation of God in Christ, then we must believe that any experience of God which is valid has an ethical quality defined by what we know of Christ. It will require with it a renewed fidelity to His teaching and example. The writer does not mean that only those who perfectly obey Christ and follow His example can be said to have the experience of God. That would be to affirm the sinlessness of Christians in a sense which he has repudiated [see 1 Jn. 1]. But unless the experience includes a setting of the affections and will in the direction of the moral principles of the Gospel, it is no true experience of God, in any Christian sense."