Holy is the Bible word for all that makes God different from us, in particular his awesome power and purity.
J. I. Packer[N]obody can produce new evidence of your depravity that will make God change his mind. For God justified you with (so to speak) his eyes open. He knew the worst about you at the time when he accepted you for Jesus' sake; and the verdict which he passed then was, and is, final.
J. I. PackerIt is not for us to imagine that we can prove the truth of Christianity by our own arguments; nobody can prove the truth of Christianity except the Holy Spirit, by his own almighty work of renewing the blinded heart. It is the sovereign prerogative of Christ's Spirit to convince men's consciences of the truth of Christ's gospel; and Christ's human witnesses must learn to ground their hopes of success not on clever presentation of the truth by man, but on powerful demonstration of the truth by the Spirit.
J. I. Packer