106 Moreover, Christ proved His love for His spotless Bride not only at the cost of immense labor and constant prayer, but by His sorrows and His sufferings which He willingly and lovingly endured for her sake. "Having loved His own...He loved them unto the end." Indeed it was only at the price of His Blood that He purchased the Church. Let us then follow gladly in the bloodstained footsteps of our King, for this is necessary to ensure our salvation: "For if we have been planted together in the likeness of His Resurrection." and "if we be dead with him, we shall live also with Him." Also our zealous love for the Church demands it, and our brotherly love for the souls she brings forth to Christ. For although our Savior's cruel passion and death merited for His Church an infinite treasure of graces, God's inscrutable providence has decreed that these graces should not be granted to us all at once; but their greater or lesser abundance will depend in no small part on our own good works, which draw down on the souls of men a rain of heavenly gifts freely bestowed by God. These heavenly gifts will surely flow more abundantly if we not only pray fervently to God, especially by participating every day if possible in the Eucharistic Sacrifice; if we not only try to relieve the distress of the needy and of the sick by works of Christian charity, but if we also set our hearts on the good things of eternity rather than on the passing things of this world; if we restrain this mortal body by voluntary mortification, denying it what is forbidden, and by forcing it to do what is hard and distasteful; and finally, if we humbly accept as from God's hands the burdens and sorrows of this present life. Thus, according to the Apostle, "we shall fill up those things that are wanting of the sufferings of Christ in our flesh for His Body, which is the Church."
Source: Mystici Corporis Christi (Vatican.va)