Chapter 17 begins to show the Israelites the value God places on blood, and therefore, on life. It also points to how valuable the shed blood of Jesus will be in securing our eternal salvation.
The beginning of Chapter 18 shows the Israelites (and us) that they (we) are slaves to God. He is King, He is sovereigns, He has the right to rule and make the rules. If they disobey they will be disciplined (ties in with Hebrews 12), if they obey they will be blessed. Obedience means avoiding the laws and lifestyles of the Canaanites and Egyptians, and instead, following the laws of God.
God then set forth sexual boundaries for the Israelites. It included who they could not marry (incest, etc) and also prohibited the sacrifice of children (abortion would be our modern day equivalent), homosexuality, and bestiality. Our society has crossed almost all those boundaries. We are to be set apart from them in this way and follow the laws of God instead of the laws of man.
Hebrews 1 Therefore, since we are surrounded by such a great cloud of witnesses, let us throw off everything that hinders and the sin that so easily entangles, and let us run with perseverance the race marked out for us. 2 Let us fix our eyes on Jesus, the author and perfecter of our faith, who for the joy set before him endured the cross, scorning its shame, and sat down at the right hand of the throne of God. 3 Consider him who endured such opposition from sinful men, so that you will not grow weary and lose heart.
The great cloud of witnesses refers to the heroes of the faith from Chapter 11. Some preachers have taught that they are witnesses to our race, cheering us on. But most preachers teach that they are not witnesses to our race, but witnesses to the blessings of living by faith - the inspiration to encourage us on our race. Whether or not believers from heaven can see us on earth is up for debate. But they certainly wouldn't be preoccupied with us - they would be preoccupied with God.
Their amazing lives of faith, their obedience of faith, their courage of faith, their acts of faith - in the face of death, persecution, hardship, unobtained promises, obtained promises, blessings, all circumstances - is an encouragement to us to run the race.
This is a marathon, not a sprint, and we need endurance and we need encouragement to keep on fighting, to keep on running to win. We are running with a purpose, not just aimlessly on a treadmill.
To do that we need to throw off sin and even things that are not necessarily sinful but that distract us from the race. Here, the writer was likely talking about the dead weight of Judaism, of legalism. We need to run by faith and faith alone. Not faith + ritual. Not faith + sacrifice. Not faith + works. Faith alone. But it could also apply to anything that distracts us from running with purpose.
We need to persevere through difficulty. We need endurance, patience, courage, hope, faith.
And the only way we can do that is to focus on Jesus - who endured the worst the world could throw at Him, for the sake of the glory of God His Father. We can't focus on the hurdles themselves. We need to keep our eyes off our feet, off the ground, off our surroundings - and focus firmly on Jesus Christ. Because He is the One and Only Perfect Example. He saw through the suffering to the ultimate and eternal victory that was His - and therefore, ours.
We need to remind ourselves that Jesus suffered opposition, that we can expect it ourselves, but that we can, and will, triumph over it!
Tomorrow's Bible In a Year Passage passage: Leviticus 19-20; Hebrews 13