The apostle Paul expressed the reason for his failure to return in person to Corinth following his first letter to the congregation. He states that reason to be “to spare you” (23). It seems that his reconsideration of possible visits was being deemed by some as a fickleness on his part, an indication of flawed character. This was not so.
In everything Paul desired to benefit the Corinthians. So, a change of plans should not be judged harshly. Paul was not lacking in dependability, his plans were not made “lightly” (16). His plans were not a matter of personal whim, that with him should be “Yes, Yes, and No, No” (17). He called upon God as his witness that his communication with the church was not a matter of his own desires, but, (true with his preaching as well), was an effort to help them “stand” in faith (23).
Paul’s efforts did indeed have God as witness. It had the Holy Spirit as a “guarantee” (22). As do others, I believe this “seal” has specific reference to God’s appointment of Paul to his work as an apostle of Jesus Christ, (cf. 1:1, “by the will of God”).