I never panic if the gate to our home is left open and the dog gets out. This is because I have trained him to salivate at the sound of a hand squeezed toy horn. Ever since he was a puppy he knows that if he hears that sound and responds, he gets a meat treat. He never fails to come running because he knows that I keep my word.
In speaking of a Godly person, Psalm 15:4 says he “swears to his own hurt, and changes not.” In other words if he says that he will do something, he will do it, even if it hurts him to keep his word. However, it’s not always possible for a human being to keep a promise. A father may promise his son a bike for Christmas, but a financial collapse or his own death may not make it possible. But God always keeps His word—because with Him, nothing is impossible. You can reply on His “exceeding great and precious promises” more than you can that the sun will be shining tomorrow.