‘But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus his Son cleanses us from all sin.'
Here is the other side of the matter. If we do come to God. If we do walk in His light, responding to His word and to His commandments. If we do open up our lives honestly so that He can reveal to us our sin and deal with it. If we do walk with Him Who gives us the light of true life which shines continually within us. Then we are coming to God as He really is (not as man thinks that He is), we are coming to the One Who is the light, Who dwells in light, and recognising Him as such. And the result will be joyous fellowship with all true believers, with all things open between us, with no sin hidden, and the further result will be that the blood of Jesus Christ, His Son, ‘goes on cleansing us' (present tense) from all sin.
It is true that John is not here dealing with the question of entry into salvation, for he assumes that already for his readers (although warning against complacency - 1 John 2:4). Rather he is talking of walking truly with God. But let us not deceive ourselves into thinking that if we see ourselves as ‘saved' we need not then worry. That we can ignore this and leave it for others. For if God is light, and that light is not producing the effect in us that the light of God should, then we must seriously ask ourselves whether we are saved at all, whether we truly know God. If God is light and we come to Him but are not affected by that light, the question is, have we come to Him at all, or simply to a god of our own imagination? For when God saves He makes His salvation effective. It may take time for that effectiveness to break through, and there may even be times of stumbling, but eventually that salvation must fully break through. And if it does not we must ask if such a person is really ‘saved', and ‘being saved'. God the Saviour does not fail in His purposes.
But on the other hand the comforting thing about it is that if we are heavy laden with our sins, and are feeling aware of our guilt, we can come constantly to God's light with a longing to be delivered, and cry to Him for forgiveness, then we can be certain sure of the cleansing that comes through the blood of Jesus. His blood (His effective sacrifice on our behalf) will cleanse us continually from all sin, known or unknown and we will be kept wholly clean in His sight.
In the words of the hymnwriter,
‘Five bleeding wounds He bears, received on Calvary,
They pour effectual prayers, they strongly plead for me,
Forgive him, O forgive, they cry,
Let not this ransomed sinner die.
And note finally the stress again on the fact that Jesus Christ is ‘His Son'. John continually stresses this uniqueness of Jesus, for there were those who failed to recognise it. He is, he says again, God's true Son, of the same nature and essence, distinct and unique and on the divine side of reality. That is why His blood, His sacrifice of Himself, can be continually effective on our behalf.