August 3

Now concerning nature, it is but the essential properties and the necessary relations inherent in the realities of things. And though these infinite realities are diverse in their character yet they are in the utmost harmony and closely connected together. As one’s vision is broadened and the matter observed carefully, it will be made certain that every reality is but an essential requisite of other realities. Thus to connect and harmonize these diverse and infinite realities an all-unifying Power is necessary, that every part of existent being may in perfect order discharge its own function. Consider the body of man, and let the part be an indication of the whole. Consider how these diverse parts and members of the human body are closely connected and harmoniously united one with the other. Every part is the essential requisite of all other parts and has a function by itself. It is the mind that is the all-unifying agency that so uniteth all the component parts one with the other that each dischargeth its specific function in perfect order, and thereby co-operation and reaction are made possible. All parts function under certain laws that are essential to existence. Should that all-unifying agency that directeth all these parts be harmed in any way there is no doubt that the constituent parts and members will cease functioning properly; and though that all-unifying agency in the temple of man be not sensed or seen and the reality thereof be unknown, yet by its effects it manifesteth itself with the greatest power. 
(‘Abdu’l-Baha, ’Tablet to August Forel’)