If We will We will send down to them a sign from the heaven before which their necks will remain (fa-zallat, [although grammatically in the past tense] is being used in the sense of the imperfect tense) bowed in humility, and they will believe (since ‘necks’ are described as ‘bowed in humility’, [a status] which in fact refers to those who possess them, the adjectival form [khādi‘ūn, ‘bowed in humility’] used therein is the one [normally] used for rational beings).