What did Paul mean when he spoke of the “unsearchable riches of Christ”?
The Apostle does not specify what is included in the “riches of Christ.” But Scripture shows many aspects of Christ’s knowledge (wisdom, teaching) that may properly be called “riches” and also “unsearchable.” They are “riches” because they have eternal worth, even providing the means to eternal life. And they are ‘unsearchable’ because, like the mysteries, they are only truly understood by those initiated, born into the family of Christ.
The riches of Christ are also unsearchable because their full value cannot be appreciated by mortal minds. Unlike anything else familiar to us, their value cannot be diminished with time or use. In fact, time will actually increase their value.
The salvation which Jesus offers is everlasting. Jesus compared it to the water of an ever flowing fountain (Rev. 7:17). The Psalmist described it as a river of pleasure (Ps. 36:8-9). The prophet Isaiah called it a well, suggesting a limitless source of supply: “With joy you will draw water from the wells of salvation” (Isa. 12:3). It is the same well of which Jesus spoke: “Whoever drinks of this water will thirst again, but whoever drinks of the water that I shall give him will never thirst. But the water that I shall give him will become in him a fountain of water springing up into everlasting life” (John 4:13-14)–again it is riches unsearchable.
Again, it may be called unsearchable riches because there is no limit to the supply available. The only limit is on the side of those receiving, who may be slow to recognize true worth. From the standpoint of God, this wisdom “was hid for ages”–until someone was ready to receive and use that knowledge.