Treasury of Scripture Knowledge
In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise,
After that ye heard
So, you Gentiles by birth should remember what you once were. You are called "Uncircumcision" by those who are called "Circumcision" [i.e., the Jews], (which refers to a physical procedure performed by people).
And though you were once estranged [from God] and were enemies [of His] in your mind because of your evil deeds,
1 Peter 2:10
At one time you [Gentiles] were not a [chosen] people, but now you are God's [special] people. Once you had not received [His] mercy, but now you have received it.
After that ye heard
[I am] assuming that you have heard Him [i.e., through the Gospel message] and were taught the truth that is in [harmony with] Jesus.
For the law was given through Moses; [but] God's favor and truth came through Jesus Christ.
Thank God that you people, who were once slaves to [the practice of] sin, became obedient from [your] heart to the pattern of teaching [i.e., the Gospel message] you committed yourself to.
[But] how can they appeal to Him if they have not [first] believed in Him? And how can they believe in Him if they have not [first] heard [about Him]? And how can they hear [about Him] if there is no preacher?
for we have heard about [the evidence of] your faith in [the service of] Christ Jesus, and about the love you have [shown] for all the saints.
1 Thessalonians 2:13
And because of this we also thank God continually that, when you people received the message of God, which you heard from us, you did not accept it as a message from [mere] human beings, but as it truly is, the message from God, which is at work in you believers.
And do not grieve God's Holy Spirit by whom you were sealed [i.e., given evidence of God's ownership] until the day of redemption [i.e., until you receive your new body in heaven. See 1:14].
Do not work for the [kind of] food that spoils, but for the kind that lasts until never ending life. The Son of man will give you this [kind of food], for God the Father has placed His seal [of approval] on Him."
He received the sign of circumcision as a seal [confirming] that he had been [considered] righteous because of the faith he had before being circumcised. Thus, he became the [spiritual] father of all people who believe [in God], even though they have not been circumcised, so that they could be considered righteous [by their faith].
2 Corinthians 1:22
He has placed His seal of ownership upon us by giving us the down payment of the Holy Spirit [to live] in our hearts.
2 Timothy 2:19
However, the solid foundation of God stands firm. [Note: This probably refers to the church. See I Tim. 3:15]. It is sealed with these words [i.e., certifying God's ownership and a commitment to Him]: "The Lord knows those who are His people," [See Num. 16:5], and "Everyone who confesses the name of the Lord should stop practicing wickedness." [See Isa. 36:13].
And I saw another angel coming up from the east; he held the seal of the living God. [Note: This "seal" was a mark of identification or ownership]. And he called out with a loud voice to the four angels who had been given [the power] to harm the land and the ocean,
If then you know how to give good gifts to your children, even though you are sinful [human beings], how much more [likely] is it that your Father in heaven will give the Holy Spirit to those who ask Him?"
And look, I [am going to] send upon you apostles what my Father promised [i.e., the Holy Spirit. See John 14:26]; but you should wait in the city [of Jerusalem] until you are clothed with power from above." [Note: This promise was fulfilled when the apostles were immersed in the Holy Spirit. See Acts 1:4 - 2:4].
"And I will ask the Father and He will give you another Helper [i.e., besides me], who will be with you forever.
"But the Helper will come, that is, the Holy Spirit of truth [i.e., who reveals truth]. He comes from the Father and I will send Him to you from the Father. [When He comes] He will give testimony about me.
Yet I am telling you the truth: It will be helpful to you for me to go away. For unless I go, the Helper [i.e., the Holy Spirit] will not come to you. But if I go, I will send Him to you.
[One day, as He was] gathered with these apostles, He urged them not to leave Jerusalem, but to wait there until they received what the Father had promised them. (Jesus had previously discussed this with them). [See Luke 24:49].
But what you see happening is simply [the fulfillment of] what was predicted by the prophet Joel [2:28ff],
[This happened] so that the blessing [promised] to Abraham might be received by the Gentiles through [the person and work of] Christ, so that we might receive the promised [gift of the] Holy Spirit through [our] faith [in Jesus].
So, in His name the [unconverted] Gentiles will have hope."