A question about the canonization of saints.

I have a theological problem. Is the process of canonization Biblically sound? I ask in particular as I was reading Mathew 7:22-7:23 states "When Judgement Day comes, many will say to me, ‘Lord, Lord! In your name we spoke God's message, by your name we drove out many demons and performed many miracles!’ Then I will say to them, ‘I never knew you. Get away from me, you wicked people!’". So to me it seems impossible to determine, by mortal men, the meaning of what a saint is if even miracles are performed.

I understand that technically there is a waiting period and that the miracles are supposed to be after-death to confirm that it is God's work. But still I am uncertain about this particular aspect.