I quoted (paraphrased) , as is usual for me and some others, Scripture:
Hebrews 10:26 If we deliberately go on sinning after we ...
Hebrews 10:26 If we deliberately go on sinning after we have received the knowledge of the truth, no further sacrifice for sins remains,
For if we
sin willfully after that we have received the knowledge of the truth,
there remains no more sacrifice for sins, if. Hebrews 6:4-6 For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost, …. Leviticus 4:2,13
To "sin willfully" in the Greek carries the idea of deliberate intention that is habitual, which stems from rejecting Christ deliberately. This is continuous action with no repentance, a matter of
practice. Now we don't walk along our daily life and "accidentally" fall into a pit called sin. We exercise our will but, the use of the participle clearly shows willful, habitual, continuous action. The
unrighteous practice sin (1 Corinthians 6:9-10; Galatians 5:19-21);
not the righteous, who are born of God (1 Corinthians 6:11; 1 John 3:9).
In regards to Hebrews 6:4-6, once enlightened means to bring to light, to shed light upon or to cause light to shine upon some object, in the sense of illuminating it. John 1:9 describes Jesus, the "true Light," giving light "to every man," but this cannot mean the light of salvation, because not every man is saved.
The light either leads to the complete acceptance of Jesus Christ or produces condemnation in those who reject the light.
In regards to "tasted of the heavenly gift and the good word of God and the powers of the age to come," they may have tasted in such a way as to give them a distinct impression of what was tasted, yet they still fell away.
Inherent in the idea of tasting is the fact that one might or might not decide to accept what is tasted. For example, the same word tasted (geuomai) is used in Matthew 27:34 to say that those crucifying Jesus "offered him wine to drink, mingled with gall;
but when he tasted it, he would not drink it." Do we taste into one Spirit or drink into one Spirit?(1 Corinthians 12:13).
In regards to partakers of the Holy Ghost, the word translated "partaker" can certainly refer to a saving partaking in Christ, as we read in Hebrews 3:14, yet it can also refer to a less than saving association or participation. See Luke 5:7 and Hebrews 1:9 - "comrades, companions," which describes one who shares with someone else as an associate in an undertaking. These Hebrews who fell away had obviously in some aspect shared in the ministry of the Holy Spirit, but in what way and to what extent? There are other ministries of the Holy Spirit which precede receiving the indwelling and sealing of the Holy Spirit, which only genuine believers receive. Such people certainly may have experienced sorrow for sin, heard and understood the gospel and have given some assent to it and have become associated with the work of the Holy Spirit while around believers, been exposed to the true preaching of the word of God, yet have
simply tasted and stopped there. The experiences in Hebrews 6:4-6 are all preliminary to those decisive beginning stages of becoming a Christian, yet some
draw back to perdition after receiving the 'knowledge' of the truth and
do not believe to the saving of the soul, as we see in (Hebrews 10:26-39)
These Hebrews who fall short of obtaining salvation certainly may have become partakers of the Holy Spirit in his pre-salvation ministry, convicting of sin and righteousness and judgment to come by tasting the good word of God and temporarily responded to His drawing power which is intended to ultimately lead unbelievers to Christ, yet the writer of Hebrews does not use conclusive terms that these individuals were "indwelled by the Holy Spirit" or "sealed by the Holy Spirit." Genuine believers who believe the gospel are sealed in Him with the Holy Spirit who is the guarantee of our inheritance until the redemption of the purchased possession/unto the day of redemption. (Ephesians 1:13-14; 4:30)