My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous: My little children - Τεκνια μου· My beloved children; the address of an affectionate father to children whom he tenderly loves. The term also refers to the apostle's authority as their spiritual father, and their obligation to obey as his spiritual children.
That ye sin not - This is the language of the whole Scripture; of every dispensation, ordinance, institution, doctrine, and word of God. Sin not - do not run into ruin; live not so as to promote your own misery; be happy, for it is the will of God that ye should be so; therefore he wills that ye should be holy: holiness and happiness are inseparable; sin and misery are equally so.
And if any man sin - If, through ignorance, inexperience, the violence of temptation, unwatchfulness, etc., ye have fallen into sin, and grieved the Spirit of God, do not continue in the sin, nor under the guilt; do not despair of being again restored to the favor of God; your case, it is true, is deeply deplorable, but not desperate; there is still hope, for -
We have an advocate with the Father - We still have him before the throne who died for our offenses, and rose again for our justification; and there he makes intercession for us. He is the righteous; he who suffered, the just for the unjust, that he might bring us to God. Do not, therefore, despair, but have immediate recourse to God through him.