So, as the Holy Spirit says:

“Today, if you hear his voice,
  do not harden your hearts
as you did in the rebellion,
    during the time of testing in the wilderness,
where your ancestors tested and tried me,
    though for forty years they saw what I did.
 That is why I was angry with that generation;
    I said, ‘Their hearts are always going astray,
    and they have not known my ways.’
So I declared on oath in my anger,
    ‘They shall never enter my rest.’ 

Hebrews 3:7-11; cf Psalm 95:7-11

As we begin, we need to recall that this is an expansion on the conditional statement in verse 6: “And we are his house, if indeed we hold firmly to our confidence and the hope in which we glory.” (Heb. 3:6b)

These verses taken from Psalm 95 recount the experience of the people in the wilderness.  You’ll remember that they kept trying God’s patience, complaining, rebelling and being disobedient in the extreme, and of all those who were saved out of Egypt, only two of them were allowed to enter the rest, the Promised Land. Not even Moses was permitted to enter into it; they all perished in the wilderness.  God had promised to deliver Abraham’s descendants out of Egypt, which He did, and into the Promised Land, which He did, even though of the ones who left Egypt, all save 2 died en route. Yet a vast number did enter the Land, but they were born during the 40 years between the exodus from Egypt and the entry into the Land, and thus we can see that God’s promise to Abraham was unconditional for the group called the descendants of Abraham, but conditional to the individuals within the group. God kept His promise to the Israelites in the Wilderness, in spite of the fact that most of them turned their backs on Him and never entered… see how this worked?

See to it, brothers and sisters, that none of you has a sinful, unbelieving heart that turns away from the living God. But encourage one another daily, as long as it is called “Today,” so that none of you may be hardened by sin’s deceitfulness. We have come to share in Christ, if indeed we hold our original conviction firmly to the very end. As has just been said:

“Today, if you hear his voice,
    do not harden your hearts
    as you did in the rebellion.”

Hebrews 3:12-15

As our attention is turned back to the “here and now” the author issues a challenge to his readers.  They are to “see to it” that they aren’t led to turn their backs on God.  Instead, they are told to “encourage one another daily, as long as it is called ‘Today'”.  As I read it, this reference to “Today” tells us that this is a command that is not just for the recipients of the letter, but for all generations until Jesus returns: Encourage one another daily, lest any should fall away from their faith!  This seems to harmonize nicely with the injunction that we love one another, don’t you think?  How can we love one another and not encourage and help our brother or sister in times of trial and testing?

With that warm and cheerful mental image of love, encouragement and community, the author drops another conditional statement: We have come to share in Christ, if indeed we hold our original conviction firmly to the very end. “Share in Christ” refers to all that we have attained in Him: Salvation, forgiveness, freedom, joy, hope, peace, sonship, eternal life, God’s family, co-heirs… all of it… IF… we hold onto our faith until the “very end.”  Then, he repeats the warning from the Psalm…

 Who were they who heard and rebelled? Were they not all those Moses led out of Egypt? And with whom was he angry for forty years? Was it not with those who sinned, whose bodies perished in the wilderness? And to whom did God swear that they would never enter his rest if not to those who disobeyed? So we see that they were not able to enter, because of their unbelief.

Hebrews 3:16-19

Hold on to your faith until the very end!  This is the clear message for both his original recipients in Nero’s Rome, undergoing persecution often unto death, and it is also the clear message to us today.  The various theologies might dispute what the alternative is, but all agree that we must hold on to our faith.

By now, three chapters into Hebrews, you should see the pattern: Something wonderful, followed by a warning, and then something wonderful…  What an amazing letter!  I hope you’ll also be seeing that it is not a theoretical kind of book, it is real, living and alive with vitality, the kind of life and vitality that can change a person’s outlook on life itself.