“Hare Rama Hare Rama Rama Rama Hare Hare
Hare Krishna Hare Krishna Krishna Krishna Hare Hare”
iti shodashakam namnam, kali-kalmasha-nashanam , natah parataropayah, sarva-vedeshu drishyate.

In Srimad Bhagavathanam, sloka 12.13.23,
"nāma-saṅkīrtanaṁ yasya
sarva-pāpa praṇāśanam
praṇāmo duḥkha-śamanas
  taṁ namāmi hariṁ param"
​states that "I offer my respectful namaskarams unto the Supreme Lord, Hari, the chanting of whose holy names destroys all sinful reactions, and the offering of namaskarams unto whom relieves all material suffering. "

In Pandava Gita, shloka45, Gautama Rishi says,
“Go koti daanam grahaneshu Kasi,
Prayaga gangayutha kalpavasa,
Yagnayutham meru swarna daanam,
Govinda namna kadhapi thulyam”
The name of Govinda is much greater than, To giving crores of cows during eclipse, Or living in Benares or Allahabad , In the shores of Ganges for thousands of eons