Without water the tree cannot flourish or even exist. Vitality is essential to a Christian. There must be life--a vital principle infused in us by God the Holy Spirit--or we cannot be trees of the Lord. Being a Christian merely in name is a dead thing; we must be filled with the spirit of divine life.
This life is mysterious. We do not understand the circulation of the water, by what force it rises, and by what power it descends again. So the life within us is a sacred mystery. Regeneration is performed by the Holy Spirit entering into man and becoming man's life; and this divine life in a believer afterwards feeds upon Christ and is in this way sustained by divine food, but how it comes and where it goes who will explain to us?
What a secret thing the water is! The roots go searching through the soil, but we cannot see them suck out the various gases or transmute the mineral into the vegetable; this work is done down in the dark. Our root is Christ Jesus, and our life is hidden in Him; this is the secret of the Lord. The source of the Christian life is as secret as the life itself.
How permanently active is the water in the cedar! In the Christian the divine life is always full of energy--not always in fruit--bearing, but in inward operations. The believer's graces are not always constant motion, but his life never ceases to palpitate within. He is not always working for God, but his heart is always living in Him. As the water reveals itself in producing the foliage and fruit of the tree, so with a truly healthy Christian, his grace is externally displayed in his walk and conversation. If you talk with him, he cannot help speaking about Jesus. If you notice his actions, you will see that he has been with Jesus. He is so full of Christ that He must fill his conduct and conversation.