Notice that it says we have forgiveness of sins. It does not say we can get forgiveness of sins.
The reality is that Jesus has once and for all time forgiven all sin for all people past, present and future.
The Sin that we should focus on is the sin of unbelief. It is what separates men from the Lord. It is what prevents us from receiving the blessings that Grace has provided.
(All other sins are an issue for men but not an issue for the HolySpirit because of the shed blood of Jesus)