There are always conditions to salvation. If a person accepts the gospel and then continues in drunkenness, fornication, stealing, etc, they hardly are saved. The saved are commanded to not sin, so a condition of salvation is that one not sin, and part of not sinning is to obey God. Of course none of us meets the condition, we can only strive after it (by the power of the Holy Spirit) and fall short (because of our sinful nature). Thankfully, our salvation is not dependent upon our works or we would be lost. (Ephesians 2:8-10)