Ask O Muhammad (s) the Children of Israel by way of rebuke how many a clear proof manifest ones such as the parting of the sea and the sending down of manna and quails which they exchanged for unbelief did We give them kam ‘how many’ is the interrogative particle linking the second object of the verb sal ‘ask’ and is also the second object of the verb ātaynā ‘We gave’ and its specifier; whoever changes God’s grace that is what God has blessed him with in the way of signs for these constitute the causes of guidance after it has come to him out of unbelief God is severe in retribution against him.