1 Thessalonians 3:1
So, when we could not stand it any longer [Note: Paul's concern for the spiritual well-being of the Thessalonian Christians became unbearable], we [i.e., I, See verse 5] thought it best to be left behind, alone, at Athens [Note: Paul was willing to labor alone at Athens, so he could send his fellow-workers to minister to others. See Acts 17],
Acts 17:15
But those who escorted Paul took him to Athens [i.e., in Greece] and, after being directed to have Silas and Timothy join him there as soon as possible, they left.
1 Thessalonians 3:5
[So], for this reason, when I could not stand it any longer, I also sent [Timothy] to find out about your faith. I was afraid that somehow the tempter [i.e., Satan] had tempted you [to give up] and that our work [on your behalf] will have become useless.
1 Thessalonians 2:17
But brothers, after we were separated from you for a short time --- in person but not in spirit --- we became all the more eager [to come to you] and strongly desired to see you in person. [Note: The word "separated" here denotes the traumatic experience of a child being forcibly removed from its parents. It had been about six months since Paul left Thessalonica under adverse circumstances].
2 Corinthians 2:13
I had no peace of mind because I did not find my brother Titus [there]. So, I said "good-bye" to them and went on to Macedonia.
2 Corinthians 11:29-30
Who is weak, and I do not feel their weakness? Who is led astray [from God], and I do not burn [i.e., with righteous anger over the one who caused it]?