We are not told whether they formed a partnership, or whether Paul worked for Aquila as an employee, but they worked together as tentmakers/leatherworkers. It was customary for a Rabbi to have learned a trade so that he could maintain himself and not need to be supported while preaching. 'Love work,' they said. 'He who does not teach his son a trade teaches him robbery.' This was Paul's trade. He always made every effort not to have to rely on gifts from local Christians. (Compare Acts 20:34; 1Co 4:12; 1 Corinthians 9:1-18; 2 Corinthians 11:9; 1 Thessalonians 2:9; 2 Thessalonians 3:7-10).
Especially having regard to what is said later we may probably assume that Aquila was already a Christian Jew (see Acts 18:26). There is certainly never any suggestion that he was one of Paul's converts and the assumption must be that he and his wife had been Christians for some time. Their meeting may have been providential, or it could be that Paul had been recommended by Christians he knew to seek out Aquila, and that was why he had ‘found' him. Or possibly when looking around for work he had been told about this Jew with rather funny ideas