Wise and good men may be guilty of oversights, which they will correct, as soon as they are aware of them. David does not try to justify what had been done amiss, nor to lay the blame on others; but he owns himself guilty, with others, of not seeking God in due order
SDA Bible Commentary (limited)
Volume 1-7
19. Appointed to sound. The leaders probably employed these cymbals to lead out in the marking of time.