Bhagavad-Gita 9.14
Always chanting My glories, endeavoring with great determination, bowing down before Me, these great souls perpetually worship Me with devotion.

Bhagavad-Gita 10.9
The thoughts of My pure devotees dwell in Me, their lives are fully devoted to My service, and they derive great satisfaction and bliss from always enlightening one another and conversing about me.

Bhagavad-Gita 10.25
Of the great sages I am Bhrigu; of vibrations I am the transcendental om. Of sacrifices I am the chanting of the holy names (japa), and of immovable things I am the Himalayas.

Srimad-Bhagavatam 1-1.1.14
Living beings who are entangled in the complicated meshes of birth and death can be freed immediately by even unconsciously chanting the holy name of Krsna, which is feared by fear personified.

Srimad-Bhagavatam 1-1.2.17
Sri Krsna, the Personality of Godhead, who is the Paramatma (Supersoul) in everyone's heart and the benefactor of the truthful devotee, cleanses desire for material enjoyment from the heart of the devotee who has developed the urge to hear His messages, which are in themselves virtuous when properly heard and chanted.

Srimad-Bhagavatam 6.3.22

etavan eva loke 'smin
pumsam dharmah parah smrtah
bhakti-yogo bhagavati
tan-nama-grahanadibhih

"Devotional service, beginning with the chanting of the holy name of the Lord, is the ultimate religious principle for the living entity in human society."

Srimad-Bhagavatam 11.5.32

krsna-varnam tvisakrsnam
sangopangastra-parsadam
yajnaih sankirtana-prayair
yajanti hi su-medhasah

"In the Age of Kali, intelligent persons perform congregational chanting to worship [Lord Caitanya,] the incarnation of Godhead who constantly sings the names of Krsna. Although His complexion is not blackish, He is Krsna Himself. He is accompanied by His associates, servants, weapons, and confidential companions."

Srimad-Bhagavatam 11.5.36

kalim sabhajayanty arya
guna jnah sara-bhaginah
yatra sankirtanenaiva
sarva-svartho 'bhilabhyate

"Those who are actually advanced in knowledge are able to appreciate the essential value of this Age of Kali. Such enlightened persons worship Kali-yuga because in this fallen age all perfection of life can easily be achieved by the performance of sankirtana."

Srimad-Bhagavatam 12.3.51

kaler dosa-nidhe rajan
asti hy eko mahan gunah
kirtanad eva krsnasya
mukta-sangah param vrajet

"My dear king, although Kali-yuga is full of faults, there is still one good quality about this age: simply by chanting the Hare Krsna maha-mantra, one can become free from material bondage and be promoted to the transcendental kingdom."

Srimad-Bhagavatam 12.3.51-2

kaler dosa-nidhe rajann
asti hy eko mahan gunah
kirtanad eva krsnasya
mukta-sangah param vrajet
krte yad dhyayato visnum
tretayam yajato makhaih
dvapare paricaryayam
kalau tad dhari-kirtanat

"The most important factor in this Age of Kali, which is an ocean of faults, is that one can be free from all contamination and become eligible to enter the kingdom of God simply by chanting the holy names. The self-realization that was achieved in the Satya millennium by meditation, in the Treta millennium by the performance of different sacrifices, and in the Dvapara millennium by worship of Lord Krsna can be achieved in the Age of Kali simply by chanting the holy names, Hare Krishna."

Srimad-Bhagavatam last verse
I offer my respectfull obeisances unto the Supreme Lord,
Hari, the congregational chanting of whose holy names
destoys all sinfill reactions, and the offering of obeisances
unto whom relieves all material suffering.

Sri Caitanya-caritamrta, Ådi-lila 3.40

kali-yuge yuga-dharma-namera pracara
tathi lagi' pita-varna caitanyavatara

"The religious practice for the Age of Kali is to broadcast the glories of the holy name. Only for this purpose has the Lord, in a yellow color, descended as Lord Caitanya."

Sri Caitanya-caritamrta, Antya-lila 4.71

tara madhye sarva-srestha nama-sankirtana
niraparadhe nama laile paya prema-dhana

"Of the nine processes of devotional service, the most important is to always chant the holy name of the Lord. If one does so, avoiding the ten kinds of offenses, one very easily obtains the most valuable love of Godhead."

Sri Caitanya-caritamrta, Ådi-lila 17.22

kali-kale nama-rupe krsna-avatara
nama haite haya sarva-jagat-nistara

"In this Age of Kali, the holy name of the Lord, the Hare Krsna maha-mantra, is the incarnation of Lord Krsna. Simply by chanting the holy name, one associates with the Lord directly. Anyone who does this is certainly delivered."

Kali-santarana Upanisad

hare krsna hare krsna
krsna krsna hare hare
hare rama hare rama
rama rama hare hare

iti sodasakam namnam
kali-kalmasa-nasanam
natah parataropayah
sarva-vedesu drsyate

"After searching through all the Vedic literature one cannot find a method of religion more sublime for this age than the chanting of Hare Krsna."

Brhan-naradiya Purana

harer nama harer nama
harer namaiva kevalam
kalau nasty eva nasty eva
nasty eva gatir anyatha

"In this age of quarrel and hypocrisy the only means of deliverance is chanting of the holy name of the Lord.
There is no other way. There is no other way. There is no other way."

harinama para ye ca
ghore kali-yuge narah
te eva krtakrtyasca
na kalir badhate hi tan
hare kesava govinda
vasudeva jaganmaya
itirayanti ye nityam
na hi tam badhate kalih

"In this dark age of Kali-yuga, sincere devotees of the Supreme Lord should leave aside all other means for liberation and take full shelter of the holy name. This is their real responsibility and duty. There is unlimited bliss in chanting the different names of Krsna: Hari, Kesava, Govinda, Vasudeva and Jaganmaya. For one who chants constantly with unflinching faith, he remains unaffected by the reverses of Kali-yuga, because his heart has become purified by chanting."

hari-nama-para ye ca
hari-kirtana tat parah
hari-puja-para ye ca
te krtarthah kalau-yuge

"Those who engage in chanting the holy name of Lord Hari (japa), are addicted to congregational chanting (kirtana) and engage in the worship of Lord Hari, have accomplished their desires in the age of Kali."

Visnu Purana: 6.2.17

dhyayan krte yajan yajnais
tretayam dvapare 'rcyan
yad apnoti tad apnoti
kalau sankirtya kesavam

"In this age there is no use in meditation, sacrifice and temple worship. Simply by chanting the holy name of Krishna- Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare-one can achieve perfect self realization."

Visnu Purana

dhyayan krte yajan yajnais-
tretayam dvapare rcayan
yadapnoti tadapnoti
kalau samkirtaya kesavam

"The supreme goal which was attained in Satya-yuga by years of prolonged meditation; in Treta-yuga by performing extensive yajnas; in Dvapara-yuga by opulent and scrupulous Deity worship; in Kali-yuga the same results are easily had simply by the chanting of the holy name."

Padma Purana, Uttara Khanda 42nd Chapter

dhyayan krte yajan yajnais
tretayam dvapare 'rcayan
yad apnoti tad apnoti
kalau sankirtya kesavam

"Whatever is achieved in Satya-yuga by meditation, in Treta by offering ritual sacrifices and in Dvapara by temple worship is achieved in Kali-yuga by chanting the names of Lord Kesava congregationally."

Padma Purana

satyam kaliyuga vipra
sri harer nama mangalam
param svastyayanam nrnam
nasty-eva gatir anyatha

"Oh brahmana, chanting of the holy name is the auspicious process in Kali Yuga. It is the highest auspiciousness for mankind. There is no other way."

Varaha Purana

krsna krsneti krsneti
svapan jagrad vrajamstatha
yo jalpati kalau nityam
krsna-rupi bhaveddhi sah

"Whoever continuously chants Lord Krsna's holy name, even in his sleep, can easily realise that the name is a direct manifestation of Krsna Himself, in spite of the influences of Kali-yuga. This has been ordained by Lord Krsna."

Skanda Purana

kali-kala kusarpasya
tiksna-damstrasya ma bhayam
govinda-nama-danena
dagdho yasyati bhasmatam

"I see that Kali-yuga is like a black, poisonous snake with a gaping mouth and fangs. But please be unperturbed dear devotees and listen with faith. Once the holy name of the Lord is being chanted, it is like igniting a forest fire which will burn to ashes the poisonous snakes within the forest."

mahabhagavata nityam
kalau smakirtaya kesavam

"The hallmark of a mahabhagavata the most elevated devotee in Kali-yuga is that he chants the holy name of the Lord constantly.

Kalisantarana Upanisad

"The sixteen names composed of thirty-two syllables are the only means to counteract the evil effects of Kali-yuga. In all the Vedas it is seen that to cross the ocean of nescience, there is no alternative to the chanting of the holy name."

Chanting of the holy names of Hari is the yuga-dharma (recommended religious process) for kali-yuga. The importance of this chanting cannot be overly stressed. Everyone should chant these holy names as much as possible.

Linga Purana

varjams-tisthan svapannasnan
svasan vakya-prapurane
nama-samkirtanam visnor-
helaya kali-vardhanam
krtva svarupatam yati
bhakti-yuktam param vrajet

"In our normal activities of eating, sleeping, sitting, dreaming, etc. to chant Krsna's names, while nullify the ill effects of Kali-yuga, is the perfection of speech. Even if a person chants Krsna's names indifferently, he will surely achieve his svarupa, or original spiritual self and attain that state beyond all material fear and lamentation. He will reach Vaikuntha, the supreme goal.

Madhvacharya, quoting Narayana Samhita,
in his Mundakopanisad Bhasya says -

dvapariyair janair visnuh
pancaratrais tu kevalam
kalau tu nama-matrena
pujyate bhagavan harih

"In the Dvapara-yuga people should worship Lord Visnu only by the regulative principles of the pancaratra and other such authorized books. In the Age of Kali, however, people should only chant the holy names of the Supreme Personality of Godhead."

Hare Krishna!