I don't know about you, but I would say that Hebrews 10:17 is good news. God sees all our sins-past, present and future-and says, "Your sins I remember no more!" The words "no more" are a strong double negative in the original Greek text. In other words, God is saying, "Your sins I will by no means ever remember!"
Has God lowered His standards? No, He is still perfectly holy. He did remember all our sins-2,000 years ago at the cross. Every sin which we have committed or will commit has been punished to the full in the body of Jesus Christ at the cross. That is why today, God remembers our sins no more. We should, therefore, not be sin-conscious.
Each time we feel condemned for our past mistakes, God wants us to remember the cross and say, "Lord Jesus, you were sentenced for this sin I committed. You bore the judgment, so God will not judge me for this sin. You were condemned for this sin, so God will not condemn me for it."
If you don't look to the cross, you will become sin-conscious and you will walk around with a certain expectation of judgment. And that expectation of judgment will give the devil a chance to get you thinking that God has something against you because of your sin.
You must come to the place where you know and believe that all your sins are forgiven, and that you are saved eternally.
Hebrews 10:12, 14 says, "But this Man [Jesus], after He had offered one sacrifice for sins forever, sat down at the right hand of God…For by one offering He has perfected forever…"
You and I are perfected forever because of Jesus' perfect work on the cross. We are perfected by God's full acceptance and perfect delight in His Son's work that has so glorified His holiness. Beloved, hear God say to you, "I will be merciful. Your sins and lawless deeds I will remember no more."