By nature we tend toward nothingness, since we came from nothing. Nothing stays our annihilation but the will and sustaining power of God. None can sustain himself a single moment. We are entirely dependent on the Creator for every breath we draw. As fallen creatures we are not only mutable, but everything in us is opposed to God.
Fallen man is inconstant.
No human being is to be depended on. If I disobey God, then I deserve to be deceived and disappointed by my fellows. People who like you today may hate you tomorrow. However unstable I may be, however fickle my friends may prove, God changes not. But, all praise to His glorious name, He is ever the same.