I Will Have Mercy on Whom I Have Mercy
If God loves Jacob and hated Esau, is there injustice on God's part? It's not about justice but mercy. It doesn't depend on human will or exertion but the will of God. He also hardens whomever He wills, like He did with Pharaoh in order to show His power. Pharaoh was already a guilty sinner and we all justly deserve God's wrath and judgement but some receive His mercy.
The video of the entire service including recorded Hebron congregational singing can be viewed here.