3rd Commandment of Firearm Safety
Don't rely on your gun's safety.
Treat every gun as if it can fire at any time, whether or not there's pressure on the trigger.
Your firearm has been carefully designed to maximize performance and safety. However, a gun's safety is a mechanical device and, like any mechanical device, it could fail.
Human error is a more likely reason for a gun safety to fail. By mistake, you may think the safety is on when it really isn't. Or the safety may have been disengaged without your knowledge. Or you could think your gun is unloaded when there's actually a cartridge or shell in it. A safety is not a substitute for common sense. It's merely a supplement to your proper handling of a firearm.
Don't touch the trigger on a firearm until you are ready to shoot. Keep your fingers away from the trigger when you're loading or unloading. And don't pull the trigger when the safety is engaged or positioned anywhere between safe and fire.
Read your instruction manual to understand the exact location and operation of your firearm's safety. Even when the safety is on, maintain control of your loaded firearm and control the direction of the muzzle. In other words, don't rely on your safety to justify careless handling. If your firearm's internal mechanisms are broken or have been altered, your firearm may fire even when the safety is on. Remember, you and your safe gun handling practices are your gun's best safety.