How does one determine what parts of the Old Testament are directly applicable to life now? For example, does Leviticus 15 still hold true? If not, how does one explain Matthew 5:17-20? Thanks for your serious consideration of these questions.
the old testament was established principally on carnal commandments and it is full of malign ordinances for: vengeance/revenge, killing with stones and knife, cursing with bitter water and conjuration, mutilation/disfigurement, hatred/rancor, neglect, etc., then, it is a "beastly" creed, of course not because the true Lord God made/gave it so, but because its unrighteous followers/worshippers have made it (to be) such, so it is a rudimental doctrine and is no longer current/relevant, now only satan can have power over it, because the true Lord God had discontinued His contribution/appurtenance in it already 2 millennia ago, except the support of Ten Commandments and all other ordinances which are not malign to the humans
Matthew 5:38-48 "Ye have heard that it hath been said, An eye for an eye, and a tooth for a tooth: But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek(ie to every human who is evil to you), turn to him the other also(ie be only Good to it). And if any man will sue thee at the law, and take away thy coat(ie anyone who think that you are unrighteous/bad, and want judge you), let him have thy cloak also(ie be always meek not only to it, but to all humans at all). And whosoever shall compel thee to go a mile(ie every who wants from you to do good (things)), go with him twain(ie go and do the Best which you succeed). Give(ie give only good things) to him that asketh thee, and from him that would borrow of thee turn not thou away. Ye have heard that it hath been said, Thou shalt love thy neighbour, and hate thine enemy. But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you; That ye may be the children of your Father which is in heaven: for he maketh his sun(ie His benediction/grace) to rise on the evil and on the good, and sendeth rain(ie His purification) on the just(ie on the believers) and on the unjust(ie and on the disbelievers). For if ye love them which love you, what reward have ye? do not even the publicans(ie the unrighteous people) the same? And if ye salute your brethren only, what do ye more |than others|? do not even the publicans so? Be ye therefore perfect, even as your Father which is in heaven is perfect.",
Mark 10:5 "And Jesus answered and said unto them, For the hardness of your heart he(ie Moses) wrote you this precept.",
John 12:31-32 "Now is the judgment of this world(ie now is the deliverance of the humankind from all malign religious law in the Heaven): now shall the prince of this world be cast out(ie now all inner/domestic power of satan will be permanently destroyed). And I, if I be lifted up from the earth, will draw all men unto me(or: will save all humans unto eternal life).",
Matthew 27:50-56 "Jesus, when he had cried again with a loud voice, yielded up the ghost. And, behold, the veil of the temple was rent in twain from the top to the bottom(ie all malign ordinances in God's covenant/testament has been annulled); and the earth did quake(ie the powers did shake), and the rocks rent(ie and the whole inner/domestic power of satan has permanently been removed/destroyed); And the graves were opened; and many bodies of the saints which slept arose, And came out of the graves after his resurrection, and went into the holy city, and appeared unto many. Now when the centurion, and they that were with him, watching Jesus, saw the earthquake, and those things that were done, they feared greatly, saying, Truly this was the Son of God. And many women were there beholding afar off, which followed Jesus from Galilee, ministering unto him: Among which was Mary Magdalene, and Mary the mother of James and Joses, and the mother of Zebedee's children.",
Colossians 2:14-15 "Blotting out the handwriting of ordinances that was against us, which was contrary to us(ie which was harmful/pernicious to the humans), and took it out of the way, nailing it to his cross; |And| having spoiled principalities(ie the unrighteous creeds/denominations) and powers, he made a shew of them openly, triumphing over them in it.",
Hebrews 8:7-13 "if that first |covenant| had been faultless, then should no place have been sought for the second. For finding fault with them, he saith, Behold, the days come, saith the Lord, when I will make a new covenant with the house of Israel and with the house of Judah: Not according to the covenant that I made with their fathers in the day when I took them by the hand to lead them out of the land of Egypt(ie out of the land of occultism and idolatry); because they continued not in my covenant, and I regarded them not, saith the Lord. For this |is| the covenant that I will make with the house of Israel(ie with the humans that still have no eternal life) after those days, saith the Lord; I will put my laws into their mind, and write them in their hearts(ie in their spirits): and I will be to them a God, and they shall be to me a people: And they shall not teach every man his neighbour, and every man his brother, saying, Know the Lord: for all shall know me, from the least to the greatest. For I will be merciful to their unrighteousness(ie I will permanently remove the unrighteousness from them), and their sins and their iniquities will I remember no more(ie I will not allow to exist sins and crimes among them any more). In that he saith, A new |covenant|, he hath made the first old. Now that which decayeth and waxeth old |is| ready to vanish away.",
Hebrews 9:1-12 "Then verily the first covenant had also ordinances of divine service, and a worldly sanctuary..... the priests went always into the first tabernacle, accomplishing the service of God. But into the second went the high priest alone once every year, not without blood, which he offered for himself, and for the errors of the people: The Holy Ghost this signifying, that the way into the holiest of all was not yet made manifest, while as the first tabernacle was yet standing: Which was a figure for the time then present, in which were offered both gifts and sacrifices, that could not make him that did the service perfect, as pertaining to the conscience; Which stood only in meats and drinks, and divers washings, and carnal ordinances, imposed on them until the time of reformation. But Christ being come an high priest of good things to come, by a greater and more perfect tabernacle, not made with hands, that is to say, not of this building; Neither by the blood of goats and calves, but by his own blood he entered in once into the holy place, having obtained eternal redemption for us."
Blessings