To arrive at the real meaning of “Not forsaking the assembling of ourselves together” we need to note its context, in the “Letter to the Hebrews.” Here in its two opening verses we see the timeframe of “The Letter to the Hebrews. “

“¹God, who at sundry times and in divers manners spake in time past unto the fathers (of Israel) by the prophets (of Israel), ²Hath in these last days spoken unto us (Israel) by his Son, whom he (God the Father) hath appointed heir of all things, by whom also he made the worlds.” (Hebrews 1:1-2)

Hebrews builds upon what was first spoken by Israel’s Old Testament prophets in “time past.” Their words were then confirmed and expanded upon by our Lord Jesus as seen in the books of Matthew through John.

• Hebrews is a book of prophecy spoken concerning Israel, extending to Israel in “the world to come.”
• Hebrews then in no way belongs to or fits our present-day age of the Gentile “body of Christ” that is based upon “the mystery” (Gk. musterion), meaning ‘the secret plan of God’” (Rom. 16:25).

The “body of Christ” exist today in an age that is set in between Israel’s past and Israel in “the world to come.” In contrast to spoken prophecy, we today enjoy the blessings of God’s now revealed “mystery (secreted program)” of pure grace for the Gentiles in this dispensational age called “the dispensation of the Grace of God” (Eph. 3:2). Each dispensation changes mankind’s relationship with God in that age.

Hebrews says “God… spoke” by the prophets and then by Jesus of Nazareth, addressing Israel in the Gospels. Thus, God’s words and will for Israel were well made known and recorded from that time. Prophecy that is spoken and written of is made known, certainly it cannot to be related to the Paul’s gospel of “the mystery (secret plan of God)” for the “body of Christ,” that had “been kept secret since the world began” (Rom. 16:25).

God’s secret (mystery) program concerning the Gentiles had been “hid in God” (Col 3:3), “kept secret (not spoken) since the world began” … until Jesus Himself revealed it… from heaven (Acts 9) … directly to Paul (Gal. 1:12) … for us in this age (cf. Eph. 3:1-5 below).

“For this cause I Paul, the prisoner of Jesus Christ for you Gentiles, ² If ye have heard of the dispensation of the grace of God which is given me to you-ward: ³How that by revelation he made known unto me ‘the mystery;’ (as I wrote afore in few words,  Whereby, when ye read, ye may understand my knowledge in the mystery of Christ) ⁵Which in other ages was NOT made known unto the sons of men, as it is now revealed unto his holy apostles and prophets (Paul and company) by the Spirit; (Ephesians 3:1-5)

Let’s now move on to consider more verses concerning God speaking to Israel, as seen in Hebrews 2.

“How shall we (Israel) escape, if we neglect so great salvation; which at the first began to be spoken by the Lord, and was confirmed unto us (Israelites) by them (the 12 Apostles) that heard him (Jesus); ⁴God also bearing them witness, both with signs and wonders, and with divers miracles, and gifts of the Holy Ghost…?” (Hebrews 2:3-4)

Here we see that the “Letter to the Hebrews” concerns that which was “spoken by the Lord” to Israel and then also “confirmed” by “the twelve” Apostles who preached Jesus’ message per His instructions.

As an aside, many of today’s preachers love to partially quote Hebrew 2:3 (above), misusing it during evangelistic meetings. They quote, “How shall we escape, if we neglect so great salvation…” to encourage people today to be saved. But, it also does not apply in this age. We need only ask, What “salvation” is this verse to the Hebrews speaking of?

This particular “salvation” is for Israel under the Law, requiring works of faith “to the end” (Matt. 10:22). This then is not our secure salvation by “the grace through faith” in Christ’s cross. No, it’s talking about the “salvation” … “which at the first began to be spoken by the Lord” to “the lost sheep of the house of Israel.” Recall that Jesus said; “…I am not sent but (except) unto the lost sheep of the house of Israel.” (Matt. 15:24). So, this is a reference to the kind of “salvation” connected to Jesus’ earthly ministry… to Israel (Rom. 15:8) and the promise of the Kingdom restored. As seen in Matthew through John this was a salvation based upon performance under the keeping of the Mosaic Law. Recall that Jesus had already said, 

“For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled.” (Matthew 5:18).

So, the “Letter to the Hebrews” is speaking of a salvation under the terms of Israel’s Mosaic Law... not today’s (100%) grace. Hebrews 2:3 says of Jesus’ words, it “was confirmed unto us by them that heard him,” that was by “the twelve” Apostles. Jesus had emphatically instructed “these twelve” as to whom they should preach this salvation “gospel of the Kingdom” under the Law, and also to whom they should… not go.

“These twelve Jesus sent forth, and commanded them, saying, Go not into the way of the Gentiles, and into any city of the Samaritans enter ye not: ⁶ But go rather to the lost sheep of the house of Israel. (Mat. 10:5-6)

The validity of their preaching is seen by that fact that as “the twelve” preached Jesus’ “gospel of the Kingdom” for Israel, as they performed “miraculous signs and wonders” (cf. Heb. 2:4). The miracles of the early Acts period were ‘signs’ to Israel, ‘giving witness to’ the Apostle’s offer of ‘the kingdom to come’ to Israel.

“God also bearing them witness, both with signs and wonders, and with divers miracles (Gk. simeon, signs), and gifts of the Holy Ghost….  ⁵For unto the angels hath he not put in subjection ‘the world to come,’ whereof we speak.” (Hebrews 2:4-5)

The miracle working period in Acts existed between Pentecost (Acts 2) and the end of the book of Acts. Paul then essentially washed his hands of fallen Israel, turning fully to the Gentiles (Act 28:28). These miraculous signs no longer had a purpose beyond the Acts, so they as Paul predicted they “ceased” (1Cor 13:8).  “Be it known therefore unto you (Israel), that the salvation of God is sent unto the Gentiles, and that they will hear it.” (Acts 28:28)

The Holy Spirit had worked miraculously in and through Israel’s Twelve Apostles to validate the offering of “the kingdom of (from) heaven” to Israel. But, as the record of the Bible tells us, Israel rejected this. Israel had a history of rejecting God, His message to them, His offer of salvation, and His Son as Messiah.

1. Israel consistently rejected God by killing the O.T. prophets He sent.
2. Then He sent “the Son,” and they crucified Him.
3. By the stoning of Stephen (cf. Acts 6:5, 7:51), Israel rejected witness of God’s Holy Ghost (Spirit) working and speaking through the Jesus’ Apostles and disciples.

Israel’s failure in Acts then was three-strikes and you’re out… for Israel, for a time (cf. Rom. 11:25, below). We see this by these verses of Paul’s recounting of Israel’s condition that account for Israel’s “fall” and the beginning of today’s Gentile age of “the church… the body of Christ.”

“Let their (Israel’s) eyes be darkened, that they may not see, and bow down their back alway. ¹I say then, Have they stumbled that they should fall? God forbid: but rather through their (Israel’s) fall salvation is come unto the Gentiles, for to provoke them to jealousy.” (Romans 11:10-11)
 “For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in.” (Romans 11:25)

So, Hebrews initially focuses on “time past,” leading… to the early Acts period, and then to “the world to come” (Heb. 2:5), all of which are totally unrelated to “the church… the body of Christ,” So, Hebrews speaks of Israel’s past and future.

So, in Hebrews 2:5 we see that the book of Hebrews is ultimately focusing upon… Israel in “the world to come,” not this present-day of grace. Israel’s future time begins with the 7-year Tribulation… which will come after the Rapture of the Gentile “body of Christ.” Thus, the writer of Hebrews is clearly not writing to or about us in this age of “the grace of God.”

Today’s Gentile age of “the grace of God” … is set between Israel’s “time past” and Israel in “the world to come.” We today live in a parenthetical time slot between Israel’s past and Israel’s future.

Uniquely, our grace age today operates upon the basis of faith in the cross-work of Jesus alone,” it is not based upon our performance under Israel’s law.  “… ye are not under the law, but under grace.” (Rom. 6:14b)

• So, as a point of fact, there’s no “body of Christ” to be seen in Hebrews.
• There is no “dispensation of the Grace of God” to be found in Hebrews.
• There’s no “revelation of the mystery (God’s secreted program)” for the Gentile “body” to be found in Hebrews.

The Letter to The Hebrews is Israel’s book, but on occasion confirms truth that dually applies to Jews and Gentiles; such as its reference to Christ’s shed blood as seen in Hebrews 9:12-14. Apart from faith in the blood of Christ, no man of any age may be saved.