For it is impossible, in the case of those who have once been enlightened and have tasted of the heavenly gift and have been made partakers of the Holy Spirit, and have tasted the good word of God and the powers of the age to come, and then have fallen away, to restore them again to repentance, since they again crucify to themselves the Son of God and put Him to open shame. - Hebrews 6:4-6
"Impossible". Many take this to mean that God somehow turns His back on those who've met these conditions thus making it impossible for them to return to Him even if they wanted to. Satan and many others deliberately use this section of verses to browbeat people with such notions but that's not what the passage here is saying. Notice the author explains why it's impossible "since they again crucify to themselves the Son of God"."Crucify to themselves" means this is an inward battle between you...and you. It's not that God has actually turned His back on you, it's that you have marginalized Christ, considering Him not worthy to be considered as a solution.
"Solution to what?" One might ask. Well here it says to restore them to repentance. "Repentance" here is not speaking unto salvation, nobody who is fused together with Christ can lose that (Eph. 1:13-14, 2:5, Col. 2:13). This is further attested to by the phrase "restore them again". A person does not continually re-enter salvation, but the Christian's walk should include regular repentance, that is, regular returning to following Jesus rather than following our flesh. But how does one return to following Him whom they picture within themselves defeated or unable to help?
The fact is there is only one alternative to our enslavement to sin, and there's only one solution in overcoming it and that's Christ. We cannot fix it ourselves, we cannot solve it, we cannot even improve upon it. The only option we have is to turn to Him, ask Him, and wait on Him, but if a person believes to themselves that Christ is once again helpless as if still nailed to the cross, would such a person count on Him to be one to rely on? Nobody asks a man without arms and legs for help tying their shoes. Likewise, if a person crucifies to themselves Jesus, then they have entered a state of holding Him up to contempt, no longer factoring in His power, His love, His faithfulness, and His wisdom. Often these people still want repentance but having marginalized Jesus down to an asset at best, they feel they must work more, try harder, understand better, and ultimately lift themselves up by their bootstraps, and sadly often attributing their own failing fleshly efforts to Christ, thus putting Him to open shame.
A person like this often stops praying for things or makes prayer a last resort. They are often unwilling to wait on God or step out on faith. But none of this should be conflated with them losing their salvation but rather that they may be losing their witness. Even Christians in the most non-repentant state may bring significant discipline upon themselves, the destruction of their flesh perhaps, but not for their condemnation but with a good purpose in mind "so that their spirit may be saved" (1 Cor. 5:5).