“In him we have redemption through his blood, the forgiveness of our trespasses, according to the riches of his grace, which he lavished upon us, in all wisdom and insight making known to us the mystery of his will, according to his purpose, which he set forth in Christ as a plan for the fullness of time, to unite all things in him, things in heaven and things on earth. In him we have obtained an inheritance, having been predestined according to the purpose of him who works all things according to the counsel of his will so that we who were the first to hope in Christ might be to the praise of his glory. In him you also, when you heard the word of truth, the gospel of your salvation, and believed in him, were sealed with the promised Holy Spirit, who is the guarantee of our inheritance until we acquire possession of it, to the praise of his glory.” Note, the Ephesians who believed in Jesus and were “sealed with the promised Holy Spirit, who is the guarantee of [their] inheritance.” That is to say, God has saved them and given them the Holy Spirit, who acts as a sort of “down-payment,” a means by which God demonstrates to the Ephesian believers that they will finally be saved, they will not ultimately fall away from Jesus. It works the same for us; God has given us the Holy Spirit as a means of guaranteeing our salvation.
“For this reason, because I have heard of your faith in the Lord Jesus and your love toward all the saints I do not cease to give thanks for you, remembering you in my prayers that the God of our Lord Jesus Christ, the Father of glory, may give you a spirit of wisdom and of revelation in the knowledge of him, having the eyes of your hearts enlightened, that you may know what is the hope to which he has called you, what are the riches of his glorious inheritance in the saints, and what is the immeasurable greatness of his power toward us who believe, according to the working of his great might that he worked in Christ when he raised him from the dead and seated him at his right hand in the heavenly places, far above all rule and authority and power and dominion, and above every name that is named, not only in this age but also in the one to come. And he put all things under his feet and gave him as head over all things to the church, which is his body, the fullness of him who fills all in all.” – Ephesians 1:7-23