'Fail' in the Bible

for a merciful God is Jehovah thy God; He doth not fail thee, nor destroy thee, nor forget the covenant of thy fathers, which He hath sworn to them.

be strong and courageous, fear not, nor be terrified because of them, for Jehovah thy God is He who is going with thee; He doth not fail thee nor forsake thee.'

and Jehovah is He who is going before thee, He himself is with thee; He doth not fail thee nor forsake thee; fear not, nor be affrighted.'