Consider Israel, according to the flesh, existing not ones eating the sacrifices, sharing of the altar? (1 Corinthians 10:18)
The cup of blessings that we bless exists not a sharing in the blood of Christ? The bread which we break exists not a sharing in the body of Christ? (1 Corinthians 10:16-17).
The people of Israel were set apart unto God. The priests were further consecrated to God for service in the temple. Blood sacrifices were made yearly for the atonement of sin but there were other offerings and sacrifices made as a propitiation for sin. The tithes and offerings, like the grain and burnt offerings, were "food offerings" to God (Leviticus 6:8-8:36). Along with other offerings like the peace and incense offerings they went up as a sweet-smelling aroma to God.
So when Paul asks to "consider Israel, according to the flesh, existing not ones eating the sacrifices, sharing of the altar?" he speaks of priests serving in the temple and how they shared or ate of the offerings and tithes, they shared in a portion of that given to God at the altar. That given to God at the altar was holy. For example, we read of the sin offering, it was very holy (Leviticus 6:25). And when the priests shared or ate of the offerings they shared in its holiness (Leviticus 6:24-30).
There was a guilt offering and parts of it were burnt as a food offering to God and every male priest ate of this, it was holy and they shared in its holiness. And the priest who offered a man's burnt offering would partake of the "flesh" of the offering. There were also grain offerings that they would make bread from and equally share among the priests (Leviticus 7:1-10).
We should always look at the old testament in the light of the new covenant in Christ. To go back to the old is to sever from Christ and fall from grace (Galatians 5:4). There is so much here to see and I admit my revelation is limited. Paul was a teacher of the Law before he met Jesus.
because by union one loaf exists that many exist one body, for we partake from the one loaf (1 Corinthians 10:17)
Christ is the one loaf. In Christ, we participate or share and partake of his blood and his flesh. There are not many sacrifices and offerings that we partake in, and there are not many loaves of bread that we share, but One because by a union in Christ, we exist of one body and partake from the one loaf. It is very important to realize, that what Christ sacrificed and offered, and because we are bound to him in a new covenant we share in the sacrifice of his offering.
We share in the altar of the sacrifice of Christ, and what is offered at the altar is holy thus we share in its holiness. We are cleansed and made holy because we share or have communion or partake of his sacrifice; his body, and his blood. This is the cup of blessing that we drink from, it is a sharing of his blood. We share in the offering of his flesh. Jesus is the bread of life that came down from heaven and all who eat of this bread will have eternal life (John 6:33). "The ones feeding on my flesh and drinking my blood has eternal life and I will raise him up on the last day, for my flesh exists real food and my blood is real drink" (John 6:54).
The priests shared that which was offered to God at the altar so as to have a share in that which was holy, thus they could come before a holy God to serve him in the temple. We share in the offering Christ made at the altar and can come boldly and confidently before God because we have this in common, union, we are cleansed and have communion in Christ.
Christ was the sacrifice and offering once and for all. We do not need to make sacrifices and offerings to atone for sin. We do not need to make food nor peace or incense offerings. We do not need to tithe, as we do not need to offer offerings as a propitiation, Jesus did that once and for all. Nor do we offer tithes so that the priests or ministers share in the holiness of that given at the altar. There is nothing no one can offer or give or sacrifice to share in holiness. It is received according to grace by faith in Jesus and paid for by the blood of his sacrifice.
"Come, everyone who thirsts, come to the waters; and he who has no money, come, buy and eat! Come, buy wine and milk without money and without price. Why spend money on that which is not bread, and your labor on that which does not satisfy? Listen carefully to Me, and eat what is good, and your soul will delight in the riches of foods" (Isaiah 55:1).
Christ is the drink and the food that we partake of freely. "Come to me all you who labor and are heavily laden, and I will give you rest" (Matthew 11:28-29). He offers real drink. "If anyone is thirsty, let him come to me and drink" (John 7:37). And Jesus offers real food. "I am the bread of life. Whoever comes to me will never hunger, and whoever believes in me will never thirst" (John 6:35). We are in a new covenant where Christ was the sacrifice and offering, the atonement for sin and the propitiation or appeasement of God's wrath for sin, once and for all, not just for us who believe but for the whole world (Romans 3:25; 1 John 2:2). This is good news!you can not drink the Lord's cup and the cup of demons, you can not partake of the Lord's table and the table of demons (1 Corinthians 10:21)
One day we drink from the cup of the Lord's blessings, its cleansing blood, its life, and peace. Then the next day we drink from the cup of demons and partake from the table of demons. Not that meat or food offered to demons is anything. The Lord's body is ours and ours the Lord's (1 Corinthians 6:12-20). We are in an intimate relationship which is another way to define communion. We are united with him, sharing, and partaking of fellowship. When we share in both "Are we provoking the Lord to jealousy, are we stronger than he?" (1 Corinthian 10:22).
It is somewhat like breaking the intimate loving relationship of marriage through infidelity. Through the joining of bodies, two become one flesh. Now, the one joined to the Lord exists one spiritually (1 Corinthians 6:16-20). We escape the corruption of this body by being joined with Christ spiritually or being a new creation in Christ. We are not joined with Christ in this sinful body, we await that part of our salvation, the redemption of our bodies. We are joined to Christ spiritually thus the body is like a building or temple existing on a corrupt earth that the Spirit of God exists in. To give our bodies to sexual immorality is to defile the body, the temple of God, to share from both the cup of the Lord and from the cup of demons, which is to be in a wretched state regarding your soul. One breaks the fellowship of life and peace and provokes the Lord to jealousy.
now he disciplines us to bring us together so that we share in his holiness (Hebrews 12:10).
The word "bring together" in this verse is συμφέρω (sympherō, from sun "together expressing association" and phero "bear, carry, bring forth") literally to collect, or bring together. God disciplines us because we are his children and he wants us to share, and have fellowship with him. He is a jealous God towards those he has chosen and loved. The word "share" in this verse is μεταλαμβάνω (metalambanō) to partake of, share in. God's discipline is for our benefit to bring us into his fullness (in sharing of wholeness, lacking in nothing; a deeper fellowship). When we sin in the body, it is like breaking that fellowship, not permanently as we see, "endure your trials to the extent God is treating you as sons," for all sons share (metochos, a partaker) in discipline for without it you are illegitimate..."