'Sure' in the Bible

Therefore it is on the principle of faith, that it might be according to grace, in order to the promise being sure to all the seed, not to that only which is of the law, but to that also which is of Abraham's faith, who is father of us all,

(and our hope for you is sure;) or whether we are encouraged, it is for your encouragement and salvation: knowing that as ye are partakers of the sufferings, so also of the encouragement.

For men indeed swear by a greater, and with them the oath is a term to all dispute, as making matters sure.

Wherefore the rather, brethren, use diligence to make your calling and election sure, for doing these things ye will never fall;