ISB ~ 2 Corinthians 1 v23

I call God to witness:An oath formula calling on God to confirm the reliability of personal testimony (Rom 1:9; Phil 1:8). Even God could bear witness that Paul’s decision to cancel one of his scheduled visits to Corinth was motivated by love, i.e., it was to spare them an inevitable confrontation by giving them time to repent and to be reconciled with him (CCC 2154).