Timothy"s visit to Corinth from Ephesus was not very tentative. Paul had already sent him (and Erastus; Acts 19:22) or was about to send him when he penned this epistle ( 1 Corinthians 4:17). Evidently Timothy"s relative youth tended to make some people look down on him, and he tended to be fearful (cf. 1 Timothy 4:12). Paul advised the Corinthians, who judged by external appearances, to give him the respect he deserved for doing the Lord"s work as Paul did, not just for Timothy"s own sake. [source][source][source]
It may have been Timothy"s report of conditions in Corinth when he returned to Ephesus that moved Paul to go directly to Corinth himself rather than waiting until he had visited Macedonia. Paul later referred to this visit as painful because while in Corinth he encountered strong opposition (cf. 2 Corinthians 2:1-8; 2 Corinthians 7:12; 2 Corinthians 12:14; 2 Corinthians 13:1-2). [source][source][source]