“God will surely do this for you, for He always does just what He says, and He is the one who invited you into this wonderful friendship with His Son, even Christ our Lord” 1 Corinthians 1:9.
You and I do not always prove faithful, but the apostle Paul wants us to know, by way of his letter to the believers in Corinth, that our God will surely do what He has promised; in this case, make us “blameless in the day of our Lord Jesus Christ” (verse 8).
The apostle wants the Corinthians to know that they can depend upon the faithfulness of God, who had begun a good work among them, and certainly would see them through to the end. He did the inviting; He would do the keeping.
Christians are able to participate with Christ in several ways. First in His trials and sufferings, for we are subjected to temptations and trials similar to His: “But rejoice, inasmuch as ye are partakers of Christ’s sufferings” (1 Peter 4:13, KJV).