Hebrews 6   In order to "press on to maturity" in Christ we must have the firm foundation or elementary principles of salvation.  
We must be "enlightened" v4  - made to see the truth of the gospel
We must have "tasted of the heavenly gift and made partakers of the Holy Spirit" v4 - experienced and made a sharer of the Holy Spirit.
We must have "tasted the good word of God" - 
We must have experienced the "powers of the age to come". - the miracle of new birth into a supernatural spiritual life.

This firm foundation is established with "repentance from dead works and of faith toward God." 
There is teaching that enables us to understand baptism, laying on of hands, the resurrection, and eternal judgement..v1-2 We should know and stand firm in sound doctrine.

We have a firm foundation because God has done the work of enlightening us.. offering us His salvation. If we receive His offer.. with genuine repentance and faith.. He gives to us His Spirit.
We "taste" or experience the Word and the Spirit of God.. We are a new creation.. a child of God.

To have this supernatural transformation and then "fall away" would leave one without any other way to be saved.  It would require a new crucifixion for a new salvation.. and that is not going to happen.
We don't need to keep going back to the basics of salvation.. if we are truly saved.

Have we genuinely repented?
Have we put our faith in God alone?
Have we tasted the Word of God?
Have we experienced the power of God's Spirit?
Have we been made new?
Do we love His name?
Do we minister, or serve one another?
Do we have the "full assurance of hope"?

If yes, then hallelujah.. we are ready to move on to "maturity" in Christ...
If not, then we need to go back to the basics.. the gospel of salvation through faith in Christ alone.

If we are truly God's redeemed children, then God's promises are for us.
This hope is ours - for we "inherit the promises" spoken to Abraham... " I will surely bess you and I will surely multiply you"  ( v14) 
God, Himself gave an oath to fulfill this promise.  He is unchangeable and His purpose remains unchanged. 
Lay hold of this promise, the writer tells us... may it be "an anchor of the soul, a hope both sure and steadfast and one which enters the veil, where Jesus has entered as a forerunner for us, having become a high priest forever according to the order of Melchizedek." ( v19-20)

Father, once again we call upon You to fill us with Your Spirit, that we might grasp all that You want us to understand from Your Word.  Thank You for the great gift of salvation!  Thank You for enlightening us to understand the basic truths and for leading us on to full assurance and maturity in Christ Jesus our Lord and High Priest.  It is in His name that we come boldly to the throne of grace to ask for help in every need.  Amen.