Passage
that according as it is written, He that boasts, let him boast in [the] Lord.
that according as it is written, He that boasts, let him boast in [the] Lord.
1 Corinthians 1:29 so that no flesh should boast before God.
1 Corinthians 1:30 But of him are *ye* in Christ Jesus, who has been made to us wisdom from God, and righteousness, and holiness, and redemption;
1 Corinthians 1:31 that according as it is written, He that boasts, let him boast in [the] Lord.
The verse centers on "written", "boasts", and "lord". It is saying that the verse draws attention to "written" and "boasts", so its meaning should be read from those terms before moving to application.
The prior verse says "But of him are ye in Christ...", giving immediate footing for "written" and "boasts". In 1 Corinthians context, the local focus is Christ, faith, and discipleship.
A plain takeaway is to answer the verse's own emphasis on "written" and "boasts" with trust shaped by these words, not by a vague optimism outside the passage.