Let me look at "the blessed man" in the interpreting symbol of this healthy and graceful tree.
The blessed life is a life of vast resource. "As a tree planted by the waters, and that spreadeth out her roots by the river." It is not watered by an occasional shower, it is unceasingly bathed by the vitalizing flood. Its rootlets are always drinking the nutritious waters of grace. The blessed life is planted on the banks of that wonderful river which takes its rise in the great white throne.
And just because of these boundless supplies, the blessed life is undisturbed in times of grave crisis and emergency. "He shall not see when heat cometh." He shall be cool when the unblessed are hot and fever-stricken. He shall "keep his head" in times of general panic. His powers of endurance shall make the world wonder! He shall "hold out" when everybody else is faint.
So shall there be nothing "sere and yellow" about him. "His leaf shall be green." His faith, and hope, and love shall remain fresh and beautiful even in "the dark and cloudy day."