Why did God prevent Silas from returning to Jerusalem?
God knew Paul and Barnabas would later have a falling out over John Mark. Therefore, He caused Silas to remain in Antioch rather than return to Jerusalem with the others. This positioned Silas to later labor with Paul after Barnabas departed.
Les explains that it pleased Silas to abide there still, and he marvels at how God works. God knew Paul and Barnabas were going to have a falling out, so He caused Silas not to go back to Jerusalem with the rest. Paul and Barnabas continued in Antioch preaching the Word. Later, the falling out occurred because of John Mark; Barnabas slipped off the scene, and Silas ascended to preeminence with Paul. Silas then traveled with Paul through Phrygia, Galatia, and on to Troas.
Notwithstanding it pleased Silas to abide there still.