[WE ARE writing] about the Word of Life [in] Him Who existed from the beginning, Whom we have heard, Whom we have seen with our [own] eyes, Whom we have gazed upon [for ourselves] and have touched with our [own] hands.
And the Life [an aspect of His being] was revealed (made manifest, demonstrated), and we saw [as eyewitnesses] and are testifying to and declare to you the Life, the eternal Life [in Him] Who already existed with the Father and Who [actually] was made visible (was revealed) to us [His followers].
What we have seen and [ourselves] heard, we are also telling you, so that you too may realize and enjoy fellowship as partners and partakers with us. And [this] fellowship that we have [which is a distinguishing mark of Christians] is with the Father and with His Son Jesus Christ (the Messiah).
And this is the message [the message of promise] which we have heard from Him and now are reporting to you: God is Light, and there is no darkness in Him at all [no, not in any way].
[So] if we say we are partakers together and enjoy fellowship with Him when we live and move and are walking about in darkness, we are [both] speaking falsely and do not live and practice the Truth [which the Gospel presents].
But if we [really] are living and walking in the Light, as He [Himself] is in the Light, we have [true, unbroken] fellowship with one another, and the blood of Jesus Christ His Son cleanses (removes) us from all sin and guilt [keeps us cleansed from sin in all its forms and manifestations].
If we say we have no sin [refusing to admit that we are sinners], we delude and lead ourselves astray, and the Truth [which the Gospel presents] is not in us [does not dwell in our hearts].
If we [freely] admit that we have sinned and confess our sins, He is faithful and just (true to His own nature and promises) and will forgive our sins [dismiss our lawlessness] and [continuously] cleanse us from all unrighteousness [everything not in conformity to His will in purpose, thought, and action].
If we say (claim) we have not sinned, we contradict His Word and make Him out to be false and a liar, and His Word is not in us [the divine message of the Gospel is not in our hearts].