not fail to # 09_1SA_02_16 # And [if] any man said unto him, Let them not fail to burn the fat presently, and [then] take [as much] as thy soul desireth; then he would answer him, [Nay]; but thou shalt give [it me] now: and if not, I will take [it] by force. 
not fail to # 09_1SA_20_05 # And David said unto Jonathan, Behold, to morrow [is] the new moon, and I should not fail to sit with the king at meat: but let me go, that I may hide myself in the field unto the third [day] at even.