ok, what is it about the Mosaic law now being obsolete that you do not understand? perhaps giving your time simply to the words of Christ has left you bereft of knowledge of other parts of the bible, apparently it would appear so!
please go away and learn what this means:
(Colossians 2:13-14) . . .He kindly forgave us all our trespasses and blotted out the handwritten document against us, which consisted of decrees and which was in opposition to us; and He has taken it out of the way by nailing it to the torture stake.
if you are having trouble i will help you.
now the proper procedure for dealing with sin is also laid out in Gods Word. If it is a minor sin, its is covered over with love,
(1 Peter 4:8) . . .Above all things, have intense love for one another, because love covers a multitude of sins.
if it is a serious sin that will bring reproach upon the congregation, and reflect badly upon the Christ, then there are also procedures for dealing with this. i have neither the time nor the inclination to go into them in depth. if i thought that you were interested in learning what they are, i might be persuaded, but i honestly think that you just want an argument. Suffice to say that Christ himself set the pattern, please also try to learn and understand the import of these words, once again, if you find anything that is ambiguous, then please let me know.
(Matthew 18:15-17) . . .“Moreover, if your brother commits a sin, go lay bare his fault between you and him alone. If he listens to you, you have gained your brother. But if he does not listen, take along with you one or two more, in order that at the mouth of two or three witnesses every matter may be established. If he does not listen to them, speak to the congregation. If he does not listen even to the congregation, let him be to you just as a man of the nations and as a tax collector.
you will note that there are three parts to the above, 1: speaking to the individual personally and trying to resolve the difficulty, 2.taking along others that the matter may be firmly established and resolved, 3.speaking to the congregation.
Paul also provided extensive details on how to deal with serious sins, but the post is long enough already.