Or 'display their force in:' see Matt. 14.2; 'fervent,' Jas. 5.16.
Imperfect tense, 'kept saying:' see Matt. 14.4. Cf. Mark 1.45.
Or 'observed him diligently.' The word has the force of 'watching closely, and keeping in mind,' whether to pay attention to, or to preserve. Which of these applications is the just one is the question. It is used four times (three besides this); twice for 'preserved,' as the wine and the bottles, Matt. 9.17; Luke 5.38; once for Mary's 'keeping' things in her heart, Luke 2.19. I should have preferred 'observed him diligently,' but that I do not find it used of a person, meaning 'paying attention to what he says.' It is used of words and opinions, but then it has still the force of 'keeping them safe.'
The meaning is doubtful: perhaps 'convenient day,' i.e. to Herodias's future purpose. Not a festival, but a leisure day.