1 Though chiefly the Lord's Passion is noticed in this Psalm, neither could the Martyrs have been strong, unless they had beheld Him, that first suffered; nor such things would they have endured in suffering, as He did, unless they had hoped for such things in the Resurrection as He had showed of Himself: but your Holiness knows that our Head is our Lord Jesus Christ, and that all that cleave unto Him are the members of Him the Head....And let no one say, that now-a-days in tribulation of passions we are not. For always you have heard this fact, how in those times the whole Church together as it were was smitten against, but now through individuals she is tried. Bound indeed is the devil, that he may not do as much as he could, that he may not do as much as he would: nevertheless, he is permitted to tempt as much as is expedient to men advancing. It is not expedient for us to be without temptations: nor should we beseech God that we be not tempted, but that we be not “led into temptation.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)