Book of Hebrews an overview

 Ch 1 God who in times past spake by the prophets, now speaks to us by His son, Jesus Christ.
Ch 2 Now we must listen to Jesus, who tasted death for every man. He took on Him the seed of Abraham.
Ch 3 Consider Christ Jesus, who was counted more worthy than Moses. Be steadfast unto the end. Recalls those wandering in the wilderness and those who could not enter into His rest because of unbelief and perished in the wilderness. We can have rest through faith in Christ.
Ch 4 As God ceased from His own works on the day of His rest, so should we seek rest in Christ. The Word of God is quick and powerful, and sharper than any twoedged sword
Ch 5 Concerning Christ being our high priest after the order of Melchisedec.  Paul rebukes those listening that though they should be teachers they need teaching themselves because they do not understand these things.
Ch 6 Paul tells his Hebrew brethren not to make salvation include works, but yet to rest on the doctrine of Christ. A reminder to  persevere and be diligent and reminder of the dangers of apostasy (verse 6)
Ch 7 Recalls Melchisedec, king of Salem (old name for Jerusalem), how even Abraham gave a tenth to. Jesus was made a priest after Melchisedec, see Gen 14:18-20 and Psalms 110 and also reminds them that perfection was not in the Levitical priesthood, but that the priesthood of Jesus is perfect because He endureth forever.
Ch 8 Paul summarizes the previous chapters - Jesus is our high priest who has obtained a more excellent ministry and is now the mediator of a better covenant. He quotes from Jeremiah 31 about the new covenant, why it came and that because it is new, the old is passed away.
Ch 9 Christ made the sacrifice once, unlike the priests who made offerings and the high priest who alone was able to enter into the most holy place (the 2nd tabernacle)
Ch 10 The Law was but a shadow of good things to come and were made every year. Paul compels us to be steadfast in our faith.
Ch 11 The substance of faith explained. Recounts things did by faith of Noah, Enoch, Moses, Abraham, Isaac and Rahab. Recounts what endless others like Gideon, Samson did great things through faith. did which cost them to suffer, yet they continued.
Ch 12 Run the race before you and endure the Lord's chastening.
Ch 13 Paul encourages us what to do and what to avoid - continue in brotherly love, avoid diverse and strange doctrines, communicate, obey them that have the rule over you (referring to a pastor). Always entertain the stranger as they might be angels.