10:21 But to Israel he saith. Quoted from Isa 65:2.
All day long I have stretched forth my hands. It presents the figure of a parent, with hands extended, appealing to a wayward child. That child was the Jewish nation. It was cast off because it would be cast off. It refused to listen to appeals. See Mt 23:37. The apostle is far from ascribing the rejection of Israel to a divine decree, but he assigns the cause to Israel itself. Just so the Savior says in the passage just referred to, How often 'would I' have gathered,... but 'ye would not'. The divine wish was that Israel should be saved, but Israel stubbornly refused.
10:21 An unbelieving and gainsaying people - Just opposite to those who believed with their hearts, and made confession with their mouths.
10:18-21 Did not the Jews know that the Gentiles were to be called in? They might have known it from Moses and Isaiah. Isaiah speaks plainly of the grace and favour of God, as going before in the receiving of the Gentiles. Was not this our own case? Did not God begin in love, and make himself known to us when we did not ask after him? The patience of God towards provoking sinners is wonderful. The time of God's patience is called a day, light as day, and fit for work and business; but limited as a day, and there is a night at the end of it. God's patience makes man's disobedience worse, and renders that the more sinful. We may wonder at the mercy of God, that his goodness is not overcome by man's badness; we may wonder at the wickedness of man, that his badness is not overcome by God's goodness. And it is a matter of joy to think that God has sent the message of grace to so many millions, by the wide spread of his gospel.
