I asked:
"Do you understand what "guaranteed an inheritance for the day of redemption" means?
Do you understand to whom this guarantee is addressed to?"
I do!
This guarantee is addressed to "THE FAITHFUL" (see Ephesians 1:1).
How many here understand what being a "faithful" Christian means?
Well, let's review exactly what Paul did say.
13 And
you also were included in Christ when you heard the message of truth, the gospel of your salvation.
When you believed, you were marked in him with a seal, the promised Holy Spirit,
14 who is a deposit guaranteeing our inheritance until the redemption of those who are God’s possession—to the praise of his glory.
If your theory were correct, please explain how this GUARANTEE could be made on those "WHEN" the believed. One's faithfulness is only seen AFTER time passes. Certainly NOT when one believe.
Using 'the faithful' in v.1 as an excuse for limiting the whole letter is silly. In fact, we find the SAME MESSAGE in ALL of Paul's epistles. And this is how he addresses some of his epistles:
1 Cor 1
1 Paul, called to be an apostle of Christ Jesus by the will of God, and our brother Sosthenes,
2 To the church of God in Corinth, to those sanctified in Christ Jesus and called to be his holy people, together with all those everywhere who call on the name of our Lord Jesus Christ—their Lord and ours:
2 Cor 1
1 Paul, an apostle of Christ Jesus by the will of God, and Timothy our brother, To the church of God in Corinth, together with all his holy people throughout Achaia:
Gal 1
1 Paul, an apostle—sent not from men nor by a man, but by Jesus Christ and God the Father, who raised him from the dead—
2 and all the brothers and sisters with me, To the churches in Galatia:
Col 1
1 Paul, an apostle of Christ Jesus by the will of God, and Timothy our brother,
2 To God’s holy people in Colossae, the faithful brothers and sisters in Christ: Grace and peace to you from God our Father.
"holy people" is because of imputed righteousness, not their own righteousnesses.
1 Thess 1:1 - Paul, Silas and Timothy, To the church of the Thessalonians in God the Father and the Lord Jesus Christ: Grace and peace to you.
2 Thess 1:1 - 1 Paul, Silas and Timothy, To the church of the Thessalonians in God our Father and the Lord Jesus Christ:
The GUARANTEE in Eph 1:13,14 is for those who BELIEVED.
You're just looking for excuses to change the clear meaning of the GUARANTEE.