Hebrews 3  "Therefore...  consider Jesus.. "   Because  - He is the Heir of all things, the radiance of God's glory, the exact representation of God's nature,  and the One for whom and through whom all things were created.. and because He became flesh and blood in order share in our humanity.. to suffer and to die.. in order to "make propitiation for the sins" of mankind and to "come to the aid of those who are tempted"..   Because He is not ashamed to call us His brothers and sisters...

Because we have become "partakers of Christ"... let us:

"Take care.. lest there should be in any one of you and evil unbelieving heart, in falling away from the living God". 

".. encourage one another day after day.. lest any one of [us] be hardened by the deceitfulness of sin." 

".. hold fast the beginning of our assurance firm until the end."


The writer compares Christ to Moses ( v2-6)

Moses was faithful to God's calling.   Christ is also faithful to God the Father.
Moses was a servant in God's house.   Christ is the Son "over His house... "
Moses is like a house.. built by God.. while Christ IS the builder.
Like Moses.. we are His house.. "if we hold fast our confidence and the boast of our hope firm until the end." 

Unfortunately, the people who first followed Moses and the Law of God, failed to remain faithful.
They "provoked" the Lord by hardening their hearts.
They sinned by being disobedient and unbelieving.
They tested the Lord, they did not "know [His] ways,"
And because of these things they incurred His wrath and were barred from entering "His rest". 

The Lord's call to us is "Today if you hear His voice, Do not harden your hearts.. " 
This is not a one time event.. this is every day that is called "Today".
Don't harden your heart.. so you don't fall away from the "living God. "
Don't harden your heart.. so you aren't deceived by sin.
Don't harden your heart.. so you lose the assurance of salvation.
We are "partakers of a heavenly calling" ... we share in.. participate in the house that Christ owns.

Jesus is the "Apostle and High Priest of our calling".  He is the "author of" our salvation.
He leads us onward into deliverance as the Prince, the Captain, the Chief and we who believe must stay in "firm" - steadfast, stable, sure - "assurance" - support and confidence - as partakers with Him.

Father in heaven,  blessed and holy is Your name.  You are God, the Maker of heaven and earth and there is no other.  I thank You for Christ, my High Priest, who even now, mediates for me at Your right hand.  Let me never harden my heart again, Lord.. but to stay near to the Living God.  Help me to stay pure and blameless from all sin and to remain firm and steadfast in my confession of faith.
May Your Name be proclaimed in our homes, in our churches, and in all of the world. Soften hearts of those who have yet to believe, that they might hear Your voice and be saved.  I ask this, Lord Jesus, in Your name. Amen.