en_tn_condensed/act/14/21.md

they had preached...They returned...they kept...They told

refers to Paul and Barnabas

that city

"Derbe"

They kept strengthening the minds of the disciples

Paul and Barnabas caused the believers to believe and grow more firmly in the truth of the gospel.

encouraging them to continue in the faith

Paul and Barnabas were encouraging them to keep trusting in Jesus.

They told them that it is through many sufferings that we must enter into the kingdom of God

This is an indirect speech quote. It can be translated using a direct speech quote as, "They told them, 'It is through many sufferings that we must enter the kingdom of God.' " (See: rc://en/ta/man/translate/figs-quotations)

they told them

"Paul and Barnabas told the believers in Lystra, Iconium and Antioch"

we must enter

Paul is including himself, Barnabas and the believers. (See: rc://en/ta/man/translate/figs-inclusive)