Prayer, active or passive mortification, even suffering has no value if it is not carried out in union with and for Christ. For love of Him. For it is Christ, and only Christ, who sanctifies our suffering. Without Him it is only worthless pain; useless and having no spiritual value. If we hope to be on intimate terms with Jesus we must be willing to suffer with Him. St. John of the Cross says, "Let Christ crucified be sufficient for thee, and with Him suffer and rest."
Giovanni di Paolo c. 1475, St. Catherine of Siena giving her heart to Christ