Blasphemy against the Holy Spirit aka "the Unpardonable Sin" is finally accomplished when we've resisted and resisted the Holy Spirit for so long, we eventually burn out the conscience and quench the Spirit -- we no longer feel the Spirit's impressions as a man no longer feels thirsty after quenching his thirst. We no longer can sense His directing power over us...we become incapable of receiving pardon because we no longer feel the need to seek it - God can't forgive us because we're incapable of asking for it. "Ye receive not because ye ask not".
Let us rejoice and be exceeding glad, and let us give the glory unto him: for the marriage of the Lamb is come, and his wife hath made herself ready. And it was given unto her that she should array herself in fine linen, bright and pure: for the fine linen is the righteous acts of the saints. And he saith unto me, Write, Blessed are they that are bidden to the marriage supper of the Lamb. And he saith unto me, These are true words of God.
If the term His wife has made herself ready equates to righteous acts that the bride has done to earn the white lined and also if saying that the works of the saints now is the white linen then we are either dressed in white now - in which case the white linen cannot be given later on - else we are presently naked or else in rags. According to my faith it is due to Him that [we] are in Christ Jesus, who became to us wisdom from God, and righteousness and sanctification, and redemption (1 Corinthians 1:30). Christ is our garment and no works no matter how worthy they are to be acknowledged in His presence can suffice to cloth us in any measure better than we are now clothed in Him - so neither can simple obedience to Him now equip us more than we are already equipped by the gift of His grace. It is the white of His garment that we would be better attending to and not scrapping for self righteous purity. If we did that then we would have filled up our obedience already.