Eph 1:3-6
"Blessed be the God and Father of our Lord Jesus Christ, who has blessed us in Christ with every spiritual blessing in the heavenly places, even as he chose us in him before the foundation of the world, that we should be holy and blameless before him in love."
The 'eulogy' of 1:3-14 is a single Greek sentence — the longest in the NT. Three Trinitarian stanzas: the Father elects (1:3-6), the Son redeems (1:7-12), the Spirit seals (1:13-14). Election (exelexato) is 'before the foundation of the world' (pro kataboles kosmou) — not based on foreseen merits.
Eph 1:13-14
"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."
The Holy Spirit as arrhabon — pledge, earnest, guarantee. The Spirit is the down payment that guarantees the full inheritance. The sequence: hear → believe → be sealed with the Spirit.