romans 16:4 Who have for my life laid down their own necks: unto whom not only I give thanks, but also all the churches of the Gentiles. - Free Bible Online

      4. who have for my life laid down--"who did for my life lay down"
      their own necks--that is, risked their lives; either at Corinth (Ac 18:6, 9, 10), or more probably at Ephesus (Ac 19:30, 31; and compare 1Co 15:32). They must have returned from Ephesus (where we last find them in the history of the Acts) to Rome, whence the edict of Claudius had banished them (Ac 18:2); and doubtless, if not the principal members of that Christian community, they were at least the most endeared to our apostle.
      unto whom not only I give thanks, but also all the churches of the Gentiles--whose special apostle this dear couple had rescued from imminent danger.

JFB.