Philadelphia (lit. brotherly love; cf. Rom. 12:10; 1 Thess. 4:9; Heb. 13:1; et al.) lay about 30 miles southeast of Sardis. A Pergamenian king, Attalus II (159-138 B.C.), founded it. The town received its name from his nickname, "Philadelphus"or "brother lover."This king had a special devotion to his brother, Eumenes II. The city stood in a wine-producing area and was the so-called gateway to central Asia Minor. The modern name of this town is Alasehir.
"It was a missionary city, founded to promote a unity of spirit, customs and loyalty within the realm, the apostle of Hellenism in an Oriental land."155
Because it experienced earthquakes from time to time more of the population than normal chose to live outside the city walls.
Jesus Christ presented Himself to these saints as holy (cf. 4:8; 6:10; Ps. 16:10; Hab. 3:3; Isa. 40:34; Mark 1:24; Luke 1:35; 4:34; John 6:69; Acts 4:27, 30; 1 Pet. 1:15; 1 John 2:20), true (genuine), and authoritative (cf. 1:5; 6:10). The "key of David"seems to refer to Isaiah 22:20-23 where Hezekiah's servant, Eliakim, received authority over David's house including access to all the king's treasures. Jesus claimed to have God's full administrative authority to distribute or not distribute all God's resources according to His will.
