Can the Devil kill you if you {really believe psalms 91}

You hear people all the time saying he believed God and he died. I like Kenneth Hagin saying, there is no better way to die than believing God in fact you better be believing God when you die. Question is what were they believing when they died. Were they walking in love were they keeping Gods word, or were they in strife, fussing and fighting or were they. Paul said tho I speak with tongues on men and angels and have not love i am become as sounding brass and a tinkling cymbal, many times we think we are in faith when we aren't we are just quoting what the pastor said but God will keep his word if we{ keep his word} in our hearts.