Source: Sahasranama Bhashya by Adi Sankara
मुहूर्तमपि यो ध्यायेन्नारायणमतन्द्रितः ।
सोऽपि स्वर्गतिमाप्नोति किं पुनस्तत्परायणः ॥
He who meditates on the immutable Lord Narayana, even for moment, attains salvation. How easy should be, then, for those who are wholly devoted to Him.
Please check these: Excerpts from a discourse by our Sri Sri Muralidhara Swamiji
Those who chant the Mahamantra even once in this Kali Yuga are assured of 'Moksha' (liberation)
Lord Krishna's auspicious Name even once heard or uttered destroys all evils or inauspiciousness. This Bhagavatha Dharma is founded and established by Lord Sri Krishna which protects the entire world.
I have uttered the name of God; I have repeated the name of Rama or Hari. How can I be a sinner?' One must have faith in the glory of God's name
The Master had the faith of a child. He immediately pointed out, 'Then why is there dirt on my body?' Krishnakishore explained, 'The inner impurities go away and not the external dirt.'
The glory of the Divine Names cannot be understood by logic, reasoning or argument
If you utter the Divine Name of the Lord, it will eliminate all your sins without leaving any residue.
Any person who Chants the Name of Krishna even only once, no matter, whether said devoutly or disdainfully, would cross the ocean of life.
Sri Sri Chandrasekharendra Saraswati Swamigal extols the greatness of Chanting the Divine Name of Lord Shiva by quoting the below mentioned Sloka in Srimad Bhagavatha
Japa even once uttered has its own good effect, whether the individual is aware or not.
Lord Rama says, "I vouch safe security against all living beings to one who comes to me only once and seeks protection (from me), saying " Rama, I am yours", such is my vow"
Chant the Mahamantra Nama kirtan :
Hare Rama Hare Rama Rama Rama Hare Hare
Hare Krishna Hare Krishna Krishna Krishna Hare Hare