"True contemplation (of the cross) is that in which the heart is crushed and the conscience smitten. You must be overwhelmed by the frightful wrath of God who so hated sin that he spared not his only begotten Son. What can the siner expect if the beloved Son was so afflicted? It must be an inexpressible and unendurable yearning that causes God's Son himself so to suffer. Ponder this and you will tremble, and the more you ponder, the deeper you will tremble.
"Take this to heart and doubt not that you are the one who killed Christ. Your sins certainly did, and when you see the nanils driven through his hands, be sure that you are pounding, and when the thorns pierce his brow, know that they are your evil thoughts. Consider that if one thorn pierced Christ you deserve on hundred thousand." (Martin Luther's Easter Book)
...looking to Jesus, the founder and perfecter of our faith, who for the joy that was set before him endured the cross, despising the shame, and is seated at the right hand of the throne of God.
Consider him who endured from sinners such hostility against himself, so that you may not grow weary or fainthearted. In your struggle against sin you have not yet resisted to the point of shedding your blood. And have you forgotten the exhortation that addresses you as sons? (Hebrews 12:2-3)