'Fail' in the Bible

And I say unto you, Make to yourselves friends by means of the mammon of unrighteousness; that, when it shall fail, they may receive you into the eternal tabernacles.

but I made supplication for thee, that thy faith fail not; and do thou, when once thou hast turned again, establish thy brethren.

And as a mantle shalt thou roll them up, As a garment, and they shall be changed: But thou art the same, And thy years shall not fail.

And what shall I more say? for the time will fail me if I tell of Gideon, Barak, Samson, Jephthah; of David and Samuel and the prophets:

Be ye free from the love of money; content with such things as ye have: for himself hath said, I will in no wise fail thee, neither will I in any wise forsake thee.