'Heirs' in the Bible

Are they not all ministering spirits, sent forth to minister for them who shall be heirs of salvation?

so that you may not become half-hearted, but be imitators of those who through faith and patient endurance are now heirs to the promises.

Wherein God, willing more abundantly to shew unto the heirs of promise the immutability of his counsel, confirmed it by an oath:

By faith he sojourned in the land of promise, as in a strange country, dwelling in tabernacles with Isaac and Jacob, the heirs with him of the same promise: