'The saints' and 'the faithful' are not two sets of people, but one.
The Apostle starts, as it were, on the surface, and goes down; takes off the uppermost layer and lets us see what is below it; begins with the flowers or the fruit, and then carries us to the root. The saints are saints because they are first of all faithful. 'Faithful' here, of course, does not mean, as it usually does in our ordinary language, 'true' and 'trusty,' 'reliable' and 'keeping our word,' but it means simply 'believing'; having faith, not in the sense of fidelity, but in the sense of trust.
The letter is addressed to the saints who are in Ephesus, and faithful in Christ Jesus. Saints are people who have been separated to God from the world. It is a name which is applied in the NT to all born-again believers. Basically the word refers to a believer's position in Christ rather than to what he is in himself. In Christ all believers are saints, even though in themselves they are not always saintly. For instance, Paul addressed the Corinthians as saints (1Co_1:2), even though it is clear from what follows that they were not all living holy lives. Yet God's will is that our practice should correspond to our position: saints should be saintly.
And faithful in Christ Jesus. The word, faithful, means “believing ones” and is thus a description of all true Christians. Of course, believers should also be faithful in the sense that they are reliable and trustworthy. But the primary thought here is that they had acknowledged Christ Jesus to be their only Lord and Savior.
The faithful
Not faithful in the sense of fidelity and perseverance, but believing, as Joh_20:27; Act_10:45. It is to be included with the saints under the one article.
To the saints ... and to the faithful - the same persons: Greek, ’to those who are saints, and faithful in Christ Jesus.’
The sanctification by God is put before man’s faith. God’s grace in the first instance sanctifies us (i:e., sets us apart in His eternal purposes as holy unto Himself); and our faith, by God’s gift, lays hold of salvation (2Th_2:13; 1Pe_1:2). Consecration to God is the idea prominent in "saints."
You want to make a distinction when there are none.
J.