13. He that hath an ear, let him hear what the Spirit saith unto
the churches.

Philadelphia was once a large and powerful city, and it continued thus
until later times. Prior to the time the Revelation was written, it had
suffered severely from repeated earthquakes, which caused it to be
almost deserted by its inhabitants. Subsequently, however, it recovered
and became a prosperous, influential city.

The character Christ assumes toward this church is that of the Holy and
True--one who will justly reward them for their patience and
perseverance--and by virtue of his possessing the key of David (a symbol
of power and authority), he is able to place before them an open door
which no man can shut.

The character of this church is wholly unlike that of the preceding. In
that, there was nothing to commend, but much to condemn; whereas to
this, all is admonition, encouragement, and promise, because they had
"kept the word of his patience" and had not denied his name. Christ knew
their works and that they were worthy of approval. They still possessed
"a little strength" and had not denied his name.

Christ, who always upholds and rewards his faithful followers, although
they be few in number and constitute the despised of earth, was not
unrighteous that he should overlook this humble congregation of devoted
disciples that had kept his word, but he made them a number of special
promises _because_ of their faith and perseverance. The first was the
assurance that he had set before them an open door which no man could
shut. A door is a means either of entrance or of escape, and signifies
that God was going to open before them a greater field of enlargement