<p>13:17 <i>If you know these things, and if you do them, you will be blessed</i>- The Lord sensed the tension between knowing and doing. To know but not do would not lead to being happy&nbsp; / blessed. And this is the root cause of a lack of joy amongst many believers; they know but do not do. The doing, of course, is radical- to be the lowest servant, to wash the feet of others, living out the spirit of the cross. To know this but not do it is to not attain happiness. The only path to Christian joy is to surrender all in the emulation of the Lord's spirit in these ways. The Lord had concluded the sermon on the mount with a similar challenge, to do what we know (see on Mt. 7:22). The &quot;things&quot; immediately in view here in John 13 were the spirit of foot washing, of radical servanthood, and death on the cross. But these were all a fulfilment in practice of the various principles outlined in the sermon on the mount.</p>