The Cross

"If the Cross of Christ is anything to the mind, it is surely everything -- the most profound reality and the sublimest mystery. One comes to realize that literally all the wealth and glory of the gospel centres here. The Cross is the pivot as well as the centre of New Testament thought. It is the exclusive mark of the Christian faith, the symbol of Christianity and its cynosure.
The more unbelievers deny its crucial character, the more do believers find in it the key to the mysteries of sin and suffering...... We find that, although the offence of the Cross remains, its magnetic power is irresistible."
Glory of the Cross by Samuel M. Zwemer quoted by John Stott in The Cross of Christ