For this purpose also I labor, striving according to His power, which mightily works within me.
For I want you to know how great a struggle I have on your behalf and for those who are at Laodicea, and for all those who have not personally seen my face, that their hearts may be encouraged, having been knit together in love, and attaining to all the wealth that comes from the full assurance of understanding, resulting in a true knowledge of God’s mystery, that is, Christ Himself.
— Colossians 1:29-2:2
When you suffer on behalf of an individual, you are usually aware of the issue you are confronting. When you struggle on behalf of the saints together, however, in principle you do not always know what you are doing or what you are going up against, and that is why we say this is a matter of struggling rather than suffering.
Someone who is struggling tries this thing and that, for he is determined to go forward at any cost and do whatever it takes for the church to be knit together in love and to enter into the full knowledge of the mystery of God, Christ. Therefore the serving ones must be prepared both to suffer on behalf of the saints individually, and to struggle on their behalf corporately.