For some reason God always chooses to display his power against the backdrop of human weakness. His remarkable works in the Bible and in history are performed using weak human vessels. I believe he does this on purpose so that we would know that the work of the Lord, the ministries and jobs he gave us, are meant to be accomplished using his power, not ours. J.I. Packer is right. Weakness is the way.
Paul said the same thing in 2 Corinthians 4:7-9. “But we have this treasure in jars of clay, to show that the surpassing power belongs to God and not to us. We are afflicted in every way, but not crushed; perplexed, but not driven to despair; persecuted, but not forsaken; struck down, but not destroyed…”