We have an Advocate with the Father – “if” we sin – not “because” we sin. Big difference between if and because.
1 John 2:1…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:
In the big scheme of things (being a member of Christ’s body) the objective is “not” to sin.