The cross of Jesus Christ is the single most offensive thing to the mind of the unbeliever. Though the resurrection may be the issue people want to debate, the cross is the root of their problem.
The cross is a reminder that we are never good enough, no matter how good we might think we are. That one truth flies in the face of those who lean to their own self-righteousness. In all my years of ministry, few “real” sinners have failed to see their need for the cross. Their problem was they thought they weren’t good enough to be saved. When shown the grace of God, the Holy Spirit did His job and quickly drew them into the kingdom.
The self-righteous are a different story. They are determined they are “good enough” the way they are. Witnessing to this type of individual is most challenging. It seems the sin of self-righteousness may be the most difficult for even the Holy Spirit to break through and lovingly convict.
We must all remember the ground at the cross is level. It makes everyone realize they are no better before the Lord than another. He died for all that all might have new life in Him. The unrepentant are all in sin before the Lord. The self-righteous and the murder, the sexual immoral, the thief, and all the rest are just alike. We all must bow the knee before the cross and repent. Then we have the privilege of standing at the empty tomb and rejoice as one in Him.