From the book "Naam or Word", written by Sant Kirpal Singh

Whenever vice predominates and virtue goes under­ground and good acts are altogether ignored, the Saints preach the spiritual sadhna or practice of Naam, for it is the easiest and the quickest remedy. In this age all indi­vidual and social acts and the performance of rites and rituals as enjoined by the scriptures are hardly of any sub­stantial use, for they are outmoded and out of time.

In this age, Kirtan (the Sound Principle) occupies the highest place (among spiritual practices).
GURU ARJAN

Sant Ravi Das testifies to this:

In Sat Yuga (the golden age) "Sat" or Truth reigned supreme;
in Treta (the silver age) sacrificial obla­tions had their day;
in Dwaper (the copper age) idol worship was the law of the land;
but in Kal Yuga (the Iron Age), Naam is the most potent and sovereign remedy.

Swami Tulsi Das Ji concurs:

Meditation (on the Sat) prevailed in the first unit of time, Yajnas or sacrifices in the second, Bhakti or loving devotion in the third and now in the fourth when evil is in the ascendant and the mind is wholly engrossed in evil like a fish in the sea, Naam or the discipline of the spirit works as the saving life line from the ocean of delusive matter.
TULSI DAS

In Kal Yuga Naam is the only precious thing,
for with the help of Naam, the devotees are saved.
GURU RAM DAS

In this Kal Yuga, all Sadhans or practices are of no avail
except that of Naam, for it alone is a potent remedy.
SWAMI SHIVDAYAL SINGH

In Kal Yuga, Naam is the only means of salvation.
Now that Kal Yuga has set in, it is the most appro­priate season for sowing the seed of Naam,
Nothing else can bear fruit now, do not be in any delusion on this account.
Nanak would gladly make an offering of himself to one who has been linked with Naam.
GURU ARJAN