'Assurance' in the Bible

Jonathan then said to David, “Go in the assurance the two of us pledged in the name of the Lord when we said: The Lord will be a witness between you and me and between my offspring and your offspring forever.” Then David left, and Jonathan went into the city.

Yet God drags away the mighty by His power;when He rises up, they have no assurance of life.

For our gospel did not come to you in word only, but also in power, in the Holy Spirit, and with much assurance. You know what kind of men we were among you for your benefit,

let us draw near with a true heart in full assurance of faith, our hearts sprinkled clean from an evil conscience and our bodies washed in pure water.