II. The second idea is that this unity of the tree is formed by unity _of life_. It is a unity brought about, not by mechanical juxtaposition, but by organic relationship. “As the branch cannot bear fruit of itself, but must abide in the vine, so neither can ye except ye abide in Me.” A ball of twine or a bag of shot cannot be called a whole. If you cut off a yard of the twine, the part cut off has all the qualities and properties of the remainder, and is perhaps more serviceable apart from the rest than in connection with it. A handful of shot is more serviceable for many purposes than a bagful, and the quantity you take out of the bag retains all the properties it had while in the bag; because there is _no common life_ in the twine or in the shot, making all the particles one whole. But take anything which is a true unity or whole—your body, for example. Different results follow here from separation. Your eye is useless taken from its place in the body. You can lend a friend your knife or your purse, and it may be more serviceable in his hands than in yours; but you cannot lend him your arms or your ears. Apart from yourself, the members of your body are useless, because here there is one common life forming one organic whole. It is thus in the relation of Christ and His followers. He and they together form one whole, _because_ one common _life_ unites them. “_As_ the branch cannot bear fruit of itself, so neither can ye.” Why can the branch bear no fruit except it abide in the vine? Because it is a _vital_ unity that makes the tree one. And what is a vital unity between persons? It can be nothing else than a spiritual unity—a unity not of a bodily kind, but inward and of the spirit. In other words, _it is a unity of purpose and of resources for attaining that purpose_. The branch is one with the tree because it draws its life from the tree and bears the fruit proper to the tree. We are one with Christ when we adopt His purpose in the world as the real governing aim of our life, and when we renew our strength for the fulfilment of that purpose by fellowship with His love for mankind and His eternal purpose to bless men. We must be content, then, to be branches. We must be content not to stand isolated and grow from a private root of our own. We must utterly renounce selfishness. Successful selfishness is absolutely impossible. The greater the apparent success of selfishness is, the more gigantic will the failure one day appear. An arm severed from the body, a branch lopped off the tree, is the true symbol of the selfish man. He will be left behind as the true progress of mankind proceeds, with no part in the common joy, stranded and dying in cold isolation. We must learn that our true life can only be lived when we recognise that we are parts of a great whole, that we are here not to prosecute any private interest of our own and win a private good for ourselves, but to forward the good that others share in and the cause that is common.