"In Him also we have obtained an inheritance, having been predestined according to His purpose who works all things after the counsel of His will, to the end that we who were the first to hope in Christ would be to the praise of His glory. In Him, you also, after listening to the message of truth, the gospel of your salvation — having also believed, you were sealed in Him with the Holy Spirit of promise, who is given as a pledge of our inheritance, with a view to the redemption of God's own possession, to the praise of His glory." (Ephesians 1:11-14)Again, in these verses, the phrase "in Him" appears twice and it is uncertain if they are meant to conclude the previous verse, meaning that one day all things will be summed up in Him and we will be to the praise of His glory in Him, or to start the next sentence meaning in Him we have obtained an inheritance and in Him we also have been sealed. Because of the double use of this phrase, I assume the later.
The translators use the English term "inheritance" twice but with different meanings. The first represents that which has been allotted to us now and the second that which shall one day be ours. Paul is contrasting the lives of those who first believed in Christ, like himself, with those who, of late, only stated believing in Him. The term "first to hope" is a single Greek word that means to believe in advance of any other evidence or confirmation. Paul says that it was the allotment (inheritance) of some to believe first and for other to believe after them. This allotment was determined by the infallible wisdom and counsel of God and was determined, not according to merit, righteousness, or piety, but solely according to God's pleasure and His good and perfect will.
Sometimes we think, "Oh, if I could have lived back then, then I would..." but the truth is that we have been chosen by God to live in this time just as Paul was chosen by God to live in his. We have our allotted time and purpose here and now just as Paul had his allotted time and purpose back them. It is foolish and harmful to wish to have the allotment of others or to wish to have lived in other times. We must recognize that we are where God determined us to be and to embrace that appointment (inheritance) from God and to live it out to its fullness. It was said of King David, "For David, after he had served the purpose of God in his own generation, fell asleep, and was laid among his fathers." (Acts 13:36) It is now our turn to serve God in our own generations, in our own station of life, and in our own communities to the praise of His glory. We must embrace that portion which God has allotted to us and see it as the inheritance of a loving God towards us, that we might use it to serve Him and the world around us. Oh, that we would be like David who said, "The Lord is the portion of my inheritance and my cup; You support my lot. The lines have fallen to me in pleasant places; indeed, my heritage is beautiful to me." (Psalms 16:5-6)
Paul says that part of the propose for those who believed first were to be as shining lights of the glory of God to those who would believe after them. In them the world was able to see the truth, and the proof, of the gospel message they were preaching. God determined that the Apostles should receive their message directly from Jesus, while those who would believed later should believe their preaching, having received it from those who, not only preached, but also demonstrated the message with their lives. In a real since, their purpose was to receive the message and ours is to believe it.
Having believed their message, God sets about to seal us with His Holy Spirit. Seals can be used to prevent things from being opened or exposed, like a seal on a door, but in Paul's day they were also marks that indicated ownership and authenticity. An object marked with a seal indicated who owned the object and a letter marked with a seal indicated the certainty that the author was who he said he was. In the same way, we are sealed with the Holy Spirit to mark our ownership by God and to declare the authenticity of what has happened to us as being done by God. The Holy Spirit is integral to the whole process of salvation. This is why Jesus said to Mary when she first met Him after His resurrection, "Stop clinging to Me, for I have not yet ascended to the Father; but go to My brethren and say to them, 'I ascend to My Father and your Father, and My God and your God." (John 20:17) For it was in ascending to the Father that the Holy Spirit was released to descend upon us.
Paul says that the Holy Spirit, among other things, has been given to us as a pledge of our inheritance. The best way to explain this is with the idea of earnest money. When someone goes to buy a house, they first put down some earnest money to hold the property until the contract is drawn up and the rest of the money is paid. It is a down payment and a promise that the full amount will be paid when the contract is finished. In the same way the Holy Spirit is the earnest of our inheritance, He is a down payment and a promise that the fullness of what is ours as sons and daughters of God will one day be ours. It is the promise of what remains for us to receive of that inheritance that is, "imperishable and undefiled and will not fade away, reserved in heaven for you, who are protected by the power of God through faith for a salvation ready to be revealed in the last time." (1 Peter 1:4-5) While we have been saved now, there is still so much more awaiting for us when we are united with Christ in heaven. The Holy Spirit not only marks us out for that inheritance, not only is He a down payment of that inheritance, but He is also proof that that inheritance exists and is waiting for us, He is our hope and joy now and our confidence for later.