Romans 9:16

‘So then it is not of him who wills, nor of him who runs, but of God who has mercy.'

‘It' clearly refers to the previous verse, speaking of God's showing of mercy, whilst the present tense of the verbs suggests that here Paul is enunciating a general principle. He is thus saying that in consequence of what God had said we can discern the general pattern that a man does not receive mercy in view of what he himself purposes (wills) or in view of what he has done, or indeed in view of what he promises to do. Neither his will nor his actions alter God's decision. Rather, because by his will and actions he is subject to judgment, his hope can only lie in the mercy of God. And God dispenses that mercy as He wills. This again stresses that in order to receive mercy there is no requirement on man's part. It is not a question of foreseen faith or works, it purely results from God's sovereign decision. Faith and works must certainly follow that decision, but ultimately salvation is of God.