keep one's powder dry

Etymology
From the maxim "Trust in God and keep your powder dry", attributed to Oliver Cromwell; in the days of muskets, soldiers needed to keep their bags of gunpowder dry so they could load their guns at short notice.

Verb

 * 1) To hold back on action until a future time; to save one's resources in case of emergency.
 * 2) * 2014, Noah Feldman, "Alito's Day in Court", BloombergView:
 * He’d for the most part refrained from any dramatic concurrences or dissents -- as though keeping his powder dry for Burwell v. Hobby Lobby, the biggest religious-liberty decision in years.
 * He’d for the most part refrained from any dramatic concurrences or dissents -- as though keeping his powder dry for Burwell v. Hobby Lobby, the biggest religious-liberty decision in years.