If I'm saved and can't lost my salvation, then can't I sin when, and as often, as I want to?
Nope, not at all.
Whoever has my commands and obeys them, he is the one who loves me. He who loves me will be loved by my Father, and I too will love him and show myself to him."
- John 14:21
That's your interpretation, and sounds so legalistic. What difference does a little sin-on-the-side really make?
Don't you know that you yourselves are God's temple and that God's Spirit lives in you?
- 1 Corinthians 3:16
But life is complicated, and sometimes there's gray areas. Who can say what's good and what's not?
"Why do you ask me about what is good?" Jesus replied. "There is only One who is good. If you want to enter life, obey the commandments."
- Matthew 19:17
But I'm dating someone who's not a believer and he/she says there's no such things as 'sin' when two people love each other. So what's the worst that can happen?
If anyone destroys God's temple, God will destroy him; for God's temple is sacred, and you are that temple.
- 1 Corinthians 3:17
Come on, be serious. Nobody thinks like that any more.
Do not deceive yourselves. If any one of you thinks he is wise by the standards of this age, he should become a "fool" so that he may become wise.
- 1 Corinthians 3:18