What is the purchased possession if it is not the soul and spirit?
The purchased possession, beyond the soul and spirit, is the body. At salvation the soul and spirit are redeemed, justified, sanctified, and complete, but the body is only partially redeemed. The Holy Spirit is given as God’s earnest or down payment of that purchased possession, which will redound to the praise of His glory.
Les explains that after hearing the word of truth, the gospel, and believing, God seals believers with the Holy Spirit of promise. That Spirit is the earnest, the down payment, of the purchased possession. Salvation is complete for the soul and spirit—redeemed, justified, sanctified—but one part of the great plan of redemption is only partial. The purchased possession is the body, the third part of us that has to be ready for eternity.
Which is the earnest of our inheritance until the redemption of the purchased possession, unto the praise of his glory.