Can you tell me who is teaching this? As I’ve said earlier, in my 48 years on this world I’ve attended numerous Southern Baptist, United Methodist, Church of the Nazerene, Church of Christ, Assembly of God and Reformed/Presbyterian services. I’ve never heard anyone say you can engage in sin without any problem. I’ve heard lots of calls to repentance and exhortation to flee from sin and live Holy lives but nothing near “Believe in Jesus then live like you want to live”.
Keep in mind that even those who believe in OSAS teach to flee sin and “Do everything for the Glory of God”. And they will say if you can continue in sin without repentance that you don’t really have a saving faith.
Even the Westminster Confession of faith says
I. Repentance unto life is an evangelical grace, the doctrine whereof is to be preached by every minister of the Gospel, as well as that of faith in Christ.
II. By it, a sinner, out of the sight and sense not only of the danger, but also of the filthiness and odiousness of his sins, as contrary to the holy nature, and righteous law of God; and upon the apprehension of His mercy in Christ to such as are penitent, so grieves for, and hates his sins, as to turn from them all unto God, purposing and endeavouring to walk with Him in all the ways of His commandments.
III. Although repentance is not to be rested in, as any satisfaction for sin, or any cause of the pardon thereof, which is the act of God’s free grace in Christ, yet it is of such necessity to all sinners, that none may expect pardon without it.