There is a Moral Law (code) that is intrinsic to every human being that was born. This Moral Law to which our moral conscience is a manifestation of, comes directly from our Creator as a prescription given us out of his love and concern for US...his most prized and loved possession. He wanted humankind to be different than the forest animals living by instinct...so he infused in all of us an actual PIECE of his very person, character, and nature. We know that something is absolutely right or wrong by allowing the Moral Law in us to be energized ; we dont create it...we discover it . If we created it, it would be just mans opinion as to whats right and wrong and without any objectivity in that regard, Hitler was not objectively wrong in murdering millions of Jews and Christians for he honestly believed it was right and so did his faithful army. We ultimately know something is wrong or right by seeing if there is FIDELITY TO THE ORIGINAL (which is how Webster defines Truth) . The Original is God and his character, person, and nature....so.... if we want to know if casual sex is wrong , we check to see if there is any fidelity to the Original (God) ., and when we do, we see that there isnt because its not of God for people to use each other for temporary satisfaction / he created sex for a lifelong commitment called marriage / he created sex to greatly stengthen the emotional bond between a husband and wife which is NOT want casual hookup Partners want in the least -- they just want a copulation with no commitment or love feelings to go with it. Heres another example : We can know that lying is always wrong because God is TRUTH and cannot lie , so with lying there is no fidelity to the original .
Now, this works out very well so long as people dont willfully suppress their God given Moral Law (Moral Conscience) , but, because mankind thinks nothing of being self centered and self serving to get what he/she wants asap....havoc , harm, destruction, and sometimes even premature death occurs as a result. This is the sad state of our world, but, God in his love provided a way for us to be reconciled back to him IF we want to be ...and that is thru the finished sacrificial death of his Son sent to earth to purposely die on the cross to pay for our many accumulated sins. Once a person recieves unto himself the calvary work of Jesus , we are reconc- iled in Gods eyes and he comes to actually live within us to give us power and victory to overcome the temptation and lure of sexual sin as well as other sins. We can walk in victory in CHrist PLUS he gaurantees us a place in Heaven for all of eternity as a supreme token of his love for us because we are now the righteousness of his Son, Christ.
So , that is the long and short of it. WHen we willfully choose to sin against God and desire our OWN way, there is always destruction, chaos, harm associated with it as a consequence. And when we willfully choose to want God and live for him, we get not only protected from the consequences...but we get blessed for being obedient and in time...it becomes easier to be more obedient to the things of God. Its our choice, but with present and eternal ramifications.
Where we spend eternity is OUR choice : If a person wants great closeness to God, he grants more of it in eternity. And if the person desires great distance from God now, he grants it much more only for all of eternity. We choose, God grants. The wise chooses God now and defers gratification (which is wrong and immoral) now, and is willing to wait for the best which is to come in eternity. The Foolish say "I want what i want and right now..im not waiting" .
Regards.