1) Spiritual wisdom and understanding about the mystery of the gospel
If we are to preach faithfully, we must above all else understand that "in Christ God was reconciling the world to himself, not counting their trespasses against them, and entrusting to us the message of reconciliation." And, "For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God" (2 Corinthians 5:19, 21). God has come to do for us what we could never have done for ourselves. This is the very heart of the gospel.2) The experience of the power of truth in our own souls
This is not just a theoretical set of truths that we are expounding. Our congregation is asking, "Is he offering bread he has never tasted, or that bread by which he himself has been nourished?"3) Skill in rightly dividing the word of God
It is not enough to merely be "a nice man." We would not accept it in any other field. Even if they were "nice men" you would not fly in an airplane if the pilot had never been in a cockpit or undergo cardiothoracic surgery performed by a man who'd never held a scalpel. People everywhere are dying under the preaching of "nice men." Let Scripture always be the source of our message. As preachers, we serve the Bible; it does not serve us.4) Spiritual discernment of our congregation
Preach to the congregation you have, not to the congregation you wish you had. God has entrusted these very real souls to your care, not some other hypothetical ones.5) A zeal for the glory of God and genuine compassion for the souls of men and women.
John Murray spoke of preaching as "a personal, passionate plea." 2 Corinthians 5:19 and 21 were mentioned earlier. Verse 20, of course fits in between them is: "Therefore, we are ambassadors for Christ, God making his appeal through us. We implore you on behalf of Christ, be reconciled to God." Preaching is not just a sharing of the facts presented in the Bible. It goes one step further to imploring people to be reconciled to God on account of those facts.
Richard Baxter once proclaimed, "I seldom come out of the pulpit but my conscience smiteth me that I have been no more serious and fervent." We should similarly be convicted that we could have done more, but at the same time be comforted by the fact that "a bruised reed he will not break, and a faintly burning wick he will not quench" (Isaiah 42:3), knowing that he is pleased to place his "treasure in jars of clay, to show that the surpassing power belongs to God and not to us."