शिशुपाल वध - मनस्वि

तुङ्गत्वमितरा नाद्रौ नेदं सिंढावगाधता ।
अलङ्घनीयताहेतुरुभयं तन्मनस्विनि ॥

- शिशुपालवध

A mountain is very high, but is not deep. An ocean is very deep, but not high. Even if you have one such quality (high or deep), it becomes very difficult for people to overcome you. People who are mentally strong have both of them. They thoughts can be very high (in ideals) at the same time being deep (in sensitivity).

- Shishupalavadha