Rom.4.16That is why it depends on faith, in order that the promise may rest on grace and be guaranteed to all his offspring—not only to the adherent of the law but also to the one who the faith of Abraham, who is the father of us all,
2Cor.1.22and who has also put his seal on us and given us his Spirit in our hearts as a guarantee.
2Cor.5.5He who has prepared us for this very thing is God, who has given us the Spirit as a guarantee.
Eph.1.14who is the guarantee of our inheritance until we acquire possession of it, to the praise of his glory.
Heb.6.17So when God desired to show more convincingly to the heirs of the promise the unchangeable character of his purpose, he guaranteed it with an oath,