I John 2  John tells us why he is writing this letter... 

"I am writing these things to you that you may not sin." (v1)  He goes on to say that he is "not writing a new commandment.. " because it has always been God's command, but "on the other hand I am writing a new commandment.. " because there is a change that has come.. " the darkness is passing away, and the true light is already shining." ( v7-8) 

He is writing.. "because  your sins are forgiven.. because you have overcome the evil one.. because you know the Father..  because you know Him who has been from the beginning.. because you are strong and the word of God abides in you.." (v12-14) 

" I have not written to you because you do not know the truth, but because you do know it, and because no lie is of the truth." ( v21)  He wrote because some were trying to deceive them.. (v26) 

As children of God, followers of Jesus Christ,  we must walk in His Light and be filled with His Truth.  John emphasizes the truths that are vital to our walk of faith:

He writes so we won't sin.. but if we do we have "an Advocate with the Father, Jesus Christ the righteous." We have found the true Savior.. Jesus who "is the propitiation for our sins.. also for those of the whole world." (v2)

The truth is that we "know that we have come to know Him, if we keep His commandments.."  To know God, John writes, is to keep the commandments.  The liar says he knows God, but he doesn't keep the commandments.. he hates. he lies.. he deceives... he walks in darkness.. he doesn't know where he is going.. he loves the things of the world.. he does not stay in fellowship with other believers.. he denies Jesus. 

When we know the Truth we know our sins have been forgiven.. we can overcome the evil one, we can be strong and the word of God abides in us. We know the Father.. we know the Son.. we know we have eternal life in Him.  We will be ready for His coming for we will walk in His righteousness. 

Father in heaven, let the Truth abide in us.. fill us with this blessed Word, that we might walk in faith, keep Your commandments, and be ready for that glorious day when our Savior comes back again. Thank You for Your grace and mercy.. thank You for the Advocate that brings us into Your love. In His precious name we pray.. Amen.