Jamieson, Fausset and Brown on 1 Timothy 5:12

12. Having--Bringing on themselves, and so having to bear as a burden (Ga 5:10) judgment from God (compare 1Ti 3:6), weighing like a load on them.

cast off their first faith--namely, pledged to Christ and the service of the Church. There could be no hardship at the age of sixty or upwards in not marrying again (end of 1Ti 5:9), for the sake of serving better the cause of Christ as presbyteresses; though, to ordinary widows, no barrier existed against remarriage (1Co 7:39). This is altogether distinct from Rome's unnatural vows of celibacy in the case of young marriageable women. The widow-presbyteresses, moreover, engaged to remain single, not as though single life were holier than married life (according to Rome's teaching), but because the interests of Christ's cause made it desirable (see on 1Ti 3:2). They had pledged "their first faith" to Christ as presbyteress widows; they now wish to transfer their faith to a husband (compare 1Co 7:32, 34).