The LEB translators sees this phrase as being something that they’ve already experienced, something that is already true of them. Thus the translators put these words in parenthesis, without inserting something in the text that is not in the Greek.
I believe the LEB has it correct. Not only because of what’s not in the Greek, but also because of what the phrase means. When we come to faith in Christ, it’s a result of the work of the Holy Spirit within our hearts. In order to see and understand the gospel of Jesus Christ, our eyes must be opened by the Holy Spirit. That is, our eyes must be “enlightened.”
The word “enlighten” is translated from the Greek word, photizo. It means to bring to light, to enlighten spiritually, to render evident, to become clear.
Thus when we come to faith in Christ, it’s because the Holy Spirit has enlightened our spiritual eyes of understanding. He’s enabled us to see the truth. He’s caused the truth of Christ and what He did for us to become clear in our minds. He speaks to our hearts and convicts us of our sins, and of our need for Christ.
Therefore, going with the translators of the LEB, Paul is saying that since the eyes of their hearts have been enlightened, they’re spiritually able to receive “a spirit of wisdom and revelation” (vs. 17).
Furthermore, because of the spiritual enlightenment they’ve received, they’re also able to “know what is the hope of his calling….etc.”
“know what is the hope of his calling”
I believe what Paul is praying for is that they would become firmly convinced (know) of their calling in Christ. He wants them to come to full understanding. This word “hope” does not have the same meaning as we use this word today. That is, it’s not about something that is uncertain that we are merely hoping for. No, our hope and calling in Christ is a sure and settled thing. However, that of course is based on a faith that endures. Our calling in Christ is settled according to an abiding faith in Him.
Thus Paul is praying that they would be at peace, and rest assured of what they have in Christ. This assurance comes through a proper knowledge and understanding. Once we understand what our salvation is all about, once we realize what our faith in Christ involves and all that we have to look forward to, it will in turn make our faith stronger. It will make our devotion to Christ stronger. It will give us strength to keep living the life that God has called us to. It enables us to trust God in all things. Enlightenment to all that we have in Christ, the hope of our calling, completely changes our perspective and approach to life. It enables us to turn away from the temporary things of this world, and to live life with eternity in view.
“what [are] the riches of the glory of his inheritance among the saints.”
First, where Paul refers to his inheritance, he’s referring the inheritance that God gives to us in Christ. We inherit from God, He does not inherit from us.
To understand this verse, it’s helpful to reverse the word order among the three key words: inheritance, glory, and riches.
Our inheritance is glorious, and this glory is characterized by riches. Why doesn’t Paul simply say, “the glory of his inheritance?” Why does he include riches? Riches refers to wealth, something of great value. Thus I believe Paul is praying that the Ephesian Christians would come to the full realization of how valuable this glorious inheritance is that we (the saints) have in Jesus, our Savior.
This realization comes through the “spirit of wisdom and revelation,” which is a result of the spiritual enlightenment given by the Holy Spirit. The more time and effort we spend studying the Word of God, the more we can see and understand all that God has blessed us with in His Son. This in turn gives us a firm foundation to grow from. It produces faith, the kind of faith that can withstand all the trials and disappointments of life. Furthermore, it provides the needed motivation to turn away from sin in order to honor God and His will in our lives.