Rev 3:10

Because you have kept the word of My perseverance, I also will keep you from the hour of testing, that hour which is about to come upon the whole world, to test those who dwell on the earth.

Rom 11:29

...for the gifts and the calling of God are irrevocable. 

Mark 6:50

for they all saw Him and were terrified. But immediately He spoke with them and said to them,

"Take courage; it is I, do not be afraid."