There's always hope as long as there is "Today."
"For he says, “In a favorable time I listened to you, and in a day of salvation I have helped you.” Behold, now is the favorable time; behold, now is the day of salvation (2Cor6:2 referencing Isaiah49:8)."
There was a time that sin separated us from God, but it is no longer sin that stands between us and God because God has dealt with sin in His Son. And indeed, it is unbelief that separates us as it did also in the OT
Hebrews 3 addresses the subject of Jesus our High Priest and the Peril of Unbelief citing Psalm 95:7 twice;
"Today, if you hear His voice, do not harden your hearts as you did in the rebellion" and the chapter concludes with the subject of why they did not enter into His rest, because of their unbelief."
Heb3: 13But exhort one another daily, as long as it is called today, so that none of you may be hardened by sin’s deceitfulness.
And Hebrews 4 cites Psalm 95 a third time speaking on the subject of entering into God's Sabbath rest. And concludes with a revisit of the subject of our great High Priest, the Living Word (Who is Active Today) with v.16
Heb3: 16Let us then approach the throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need.
I can't think of any time that I'm in that isn't 'now' my time of need.