A study in the book of Revelation.
We have now come to the sixth letter, sent to one of the Asian churches, where the inscription, showing to whom it was more immediately designed: The angel of the church of Philadelphia, which was a city in Asia Minor, seated upon the borders of Mysia and Lydia, and had its name from that brotherly love for which it was eminent. Philadelphia was a border town, standing where the boundaries of Lydia, Mysia and Phrygia met, and founded to be a missionary of Greek language and culture. It was situated on the road of the imperial postal service. Philadelphia was the ancient name given due to the love and kindness that its citizens had and showed to each other as a civil fraternity. This was an excellent spirit, and, when sanctified by the grace of the gospel, would render them an excellent church, as indeed they were, for here is no one fault found with this church, and yet, doubtless, there were faults in it of common infirmity; but love covers such faults. Jesus alone is the universal head of all the churches; he wanted this church to know exactly who he is by way of the titles that he self-ascribed: He that is holy, he that is true, he that hath the key of David, he that openeth, and no man shutteth; and shutteth, and no man openeth. This was more than introduction, rather he gives them insight into the personal characteristics of their Lord and Savior: He that is holy and he that is true, holy in his nature, and therefore he cannot but be true to his word, the Bible says that there is no guile found in his mouth. The word guile is defined as sly or having cunning intelligence. Jesus speaks in his holiness which is pure and honest.
