Hebrews 6:4

For it is impossible for those who were once enlightened - Before I proceed to explain the different terms in these verses, it is necessary to give my opinion of their design and meaning:

1. I do not consider them as having any reference to any person professing Christianity.

They do not belong, nor are they applicable, to backsliders of any kind.

They belong to apostates from Christianity; to such as reject the whole Christian system, and its author, the Lord Jesus.

And to those of them only who join with the blaspheming Jews, call Christ an impostor, and vindicate his murderers in having crucified him as a malefactor; and thus they render their salvation impossible, by wilfully and maliciously rejecting the Lord that bought them. No man believing in the Lord Jesus as the great sacrifice for sin, and acknowledging Christianity as a Divine revelation, is here intended, though he may have unfortunately backslidden from any degree of the salvation of God.

The design of these solemn words is evidently, First, to show the Hebrews that apostasy from the highest degrees of grace was possible; and that those who were highest in the favor of God might sin against him, lose it, and perish everlastingly. Secondly, to warn them against such an awful state of perdition, that they might not be led away, by either the persuasions or persecutions of their countrymen, from the truth of the heavenly doctrine which had been delivered to them. And, Thirdly, to point out the destruction which was shortly to come upon the Jewish nation.

Once enlightened - Thoroughly instructed in the nature and design of the Christian religion, having received the knowledge of the truth, Hebrews 10:32 ; and being convinced of sin, righteousness, and judgment, and led to Jesus the Savior of sinners.

Tasted of the heavenly gift - Having received the knowledge of salvation by the remission of sins, through the Day Spring which from on high had visited them; such having received Christ, the heavenly gift of God's infinite love, John 3:16 ; the living bread that came down from heaven, John 6:51 ; and thus tasting that the Lord is gracious; 1 Peter 2:3 , and witnessing the full effects of the Christian religion.

Partakers of the Holy Ghost - The Spirit himself witnessing with their spirits that they were the children of God, and thus assuring them of God's mercy towards them, and of the efficacy of the atonement through which they had received such blessings.