1 Corinthians 1:4-9 is Paul's way of letting the church at Corinth know he is thankful for them and that he is praying for them. This is another example of Paul's love for the church. Paul is thankful that God saved them because they confirm the testimony of Paul and the other apostles that about Jesus...Paul uses, "Christ Jesus" here to be clear about Jesus as the Savior. He also says, "in every way you were enriched in him in all speech and all knowledge...so that you are not lacking in any spiritual gifts." Although no one has all the spiritual gifts on their own, the church of Corinth had people with all sorts of gifts that came together to as one church (although later we will see there was some division in the church). Paul indicates that they do have a well rounded group of believers that were bold and spoke the truth of Jesus as Savior. Paul reminds the church that the Lord will sustain them until Christ returns.
We should be involved in our churches. It takes everyone to have a well rounded, spiritually gifted church. We all have different abilities and levels of some giftedness. We need to participate for the betterment of the church, the furtherance of the kingdom of God, and for our own spiritual health.