Paul's concern for the growing and persecuted church in Thessalonica was deeply heartfelt and agonised, like that of a devoted parent separated from their child (1 Thessalonians 2:11).  It was not wrong, nor a sign of Paul's lack of confidence in God: it was the evidence of loving responsibility.  The apostle was accountable to God for that church (Hebrews 13:17), and Paul wanted to do whatever he could to support and encourage the believers there.
 
Paul’s departure from Thessalonica was an emergency evacuation under cover of darkness as he was being hunted by a mob (Acts 17:5-10), but he wanted to go back.  However, the Lord did not let him return: the gospel still had to be preached in more cities while there was still opportunity.  So, Paul and Silas sent Timothy.  He was a trusted pastor and teacher, well gifted to encourage and stabilise the church as it faced opposition.  Paul had personally experienced the hatred against Christians in that city.  The troubles they experienced were real and hard, and had painful effects.  They all found out that true faith in Christ involves both believing in Christ and suffering for Him (Philippians 1:29).

Paul did not gloss over the problems, nor replace them by useless sentimentality or unreal ‘triumphalism’.  The so-called ‘prosperity gospel’ could not live in Thessalonica - because they knew that tough tests were badges of honour rather than marks of spiritual failure.  Paul’s personal experience was that suffering was normal (2 Corinthians 6:3-10).  His pastoral instinct was to encourage the Thessalonians to be strong in Christ.  He recognised that young Christians, like young children, need affirming encouragement in tough times.  Timothy gave them truth to counter Satan’s lies and encourage them so that they would remain true to Christ.

It is right to be concerned for brothers and sisters who are going through difficult circumstances (2 Corinthians 11:28).  Satan lies about the future (John 8:44) and makes up frightening scenarios to prevent God's people from serving wholeheartedly.  So, we all need that pastoral care from the Lord and His under-shepherds.  The basis of pastoral care is not human sympathy but heavenly strengthening through God's Word, applied to our situation and countering the natural reactions of our hearts.  As in the gym, the struggles make you strong.  Bible-based faith will always grow when it is tested.