In plain words
The flower that blossomed in the morning withers by evening. In the same way the body too passes from youth into old age. You must understand this nature of the body.
Swami's example
Students! Keep your body and your mind under control; restrain your senses. Then you will stay young always. I Myself am the direct proof of this. Can anyone imagine that the age of this body is 75 years? I have no time, but even now I can run well. All powers are in Me; there is no weakness of any kind. What is the reason for this? In Me there are Purity, Patience, Perseverance. All three are there; there are feelings that are pure, spotless and steady. You too develop such feelings. You call yourselves Swami's devotees, do you not? Then should you not take into yourselves at least one part in a thousand of the purity that is in Swami? Along with purity you must also cultivate calm. If someone asks you something, you must answer calmly. Look at Me. However many people come, I talk with them all and am calm at all times. I have not just one work but ever so many works. It is not possible to say that My Job is such and such, or that My department is such and such. All the departments are Mine! For Me there is no such thing as rest. Even so, I am always in Ānanda. (I am always blissful)
On the birthday some people say, ‘Swami! Happy birthday.’ But I am always ‘happy’. Give Ānanda to those who are without it. Union with God: that is Ānanda. So believe firmly that God is ever in your house, with you and beside you. Then there is no way for sorrow or grief to come to you. You speak of grief, you speak of sorrow. I long to see what they are like. But they never come near Me. What is the reason? They never come to a place where there is purity.