The laws pertaining to literal Israel had to change, when spiritual Israel composed of all in Christ Jesus our Lord was established by Him. Many of the laws being fulfilled had to change, having no more meaning and or even becoming an affront to God if continued after our Lord's sacrifice. The literal temple is no more. Literal sacrifices are no more. Christ and His church both corporately and individually are the New Covenant Temple of God. Christ's sacrifice, and the willing sacrifice of His followers in Him are the New Covenant sacrifices and offerings. To reestablish these practices and therefore the laws related to them again, would be an affront to God. He having replaced them with the reality they only ever represented, according exactly to His plan from the beginning. Nevertheless, these are the very things certain apostate "Christian" entities have established again through false priesthoods, doctrines, and practices which place fallen humanity between God and the sinner again. Making humanity dependent upon them, rather than God through Christ our Lord again.
Apart from this are the many civil laws which pertained to literal Israel which simply no longer even have any relation to peoples daily lives and practice now. The moral law of God, written and spoken to humanity by God Himself, will of course always remain relevant and the standard for all in Christ Jesus our Lord. As Christ Jesus our Lord Himself testified along with many other New Testament scripture. Even still pertaining to it though, we now have the superior testimony of that moral law being lived out perfectly in the flesh, in and through our Lord and Savior Jesus Christ. As Jaime has pointed out, expanding the principles of the law taught and lived out in the life of our savior as our living example in all things. These things are not hidden from humanity, but may be easily worked out and understood by all seeking truth, and willfully submitting to it when discovered. It is the latter part that we struggle with the most. The main confusion on the matter is again the unlearned who twist the words of mainly Paul concerning such things. Or those who simply do not wish to submit to this or that scriptural teaching, either ignoring or creating arguments from twisting scripture itself as well.
Wanting to keep laws designed for literal Israel itself in this New Covenant era is fine for any who wish to do so, but demanding they must be kept by all is another issue altogether. Some of which as already stated, would compose nothing but an affront to God, and the sacrifice of His Son and His teachings.
Joh 4:19 The woman saith unto him, Sir, I perceive that thou art a prophet. 20 Our fathers worshipped in this mountain; and ye say, that in Jerusalem is the place where men ought to worship. 21 Jesus saith unto her, Woman, believe me, the hour cometh, when ye shall neither in this mountain, nor yet at Jerusalem, worship the Father. 22 Ye worship ye know not what: we know what we worship: for salvation is of the Jews. 23 But the hour cometh, and now is, when the true worshippers shall worship the Father in spirit and in truth: for the Father seeketh such to worship him. 24 God is a Spirit: and they that worship him must worship him in spirit and in truth.