Hinduism is thought by some to be the oldest religion in the world. . Buddhism grew out of Hinduism, so even though they have their differences, it is possible to speak of similarities as well. One similarity is their emphasis on living in the here-and-now.
Hinduism roots life in the present moment through the word ‘VartamAna.’ It simultaneously means ‘living’ and ‘present moment.’ Hinduism holds the two together in a singular reality, with the resulting meaning, “We live in the present time.” 
But this is not merely existence. Present-moment living is revealed in the Vedas as an active engagement with life. The image is that of sowing and reaping, similar to Paul’s own teaching, “You reap whatever you sow” (Galatians 6:7). From this belief, Hinduism establishes Vartamana Karma” as one of the main expressions of karma. 
Karma is not ‘fate’ as it is often thought to be; rather it is the effort we make to sow good seeds (especially love and compassion in Hinduism), so that our present-moment existence enriches life. Vartamana Karma is not so much about what we get back as it is about what we give. But whether we receive or give, Hinduism teaches we live in the present moment.
Buddhism continues the same idea. Thich Nhat Hanh says it simply, “Life is accessible only in the here and now.”  Interestingly, he sees Jesus’ teaching about the Kingdom of God as a commendation of present-moment living, concluding that “The Kingdom of God is now or never.” 
Just as in Hinduism, so too in Buddhism, living in the present moment is not merely a state of being, it is also a practice: mindfulness. This is the Buddhist equivalent of Christian meditation, a practice that creates the contemplative life. This life is essentially ethical (productive of comprehensive goodness, and when lived, it gives us deep joy.  Living in the present moment creates what the Dalai Lama calls, “the good heart.” It is noteworthy that it is in this kind of heart where he sees the major link between Buddhism and the teachings of Jesus. 
Putting everything together, Hinduism and Buddhism teach present-moment living simply because it is only here-and-now where truth is living faith. Putting truth in the past or the future reduces it to an abstract concept, which it was never meant to be.
 Others believe it is Zoroastrianism. It is difficult, if not impossible, to say for sure which of the two religions is earliest because they are both believed to have arisen 2000+/- BCE.
. Definition taken from Spoken Sanskrit, an online source cited by Hindus themselves as a good reference.
 Arkadeb Bhattacharyya, “The Four Kinds of Karma,” Prana World, June 6, 2017.
 Thich Nhat Hanh, ‘You Are Here: Discovering the Magic of the Present Moment’ (Shambala, 2009), 9.
 Ibid., 10.
 The Dalai Lama has emphasized the ethical and joyful nature of mindfulness in his writings and public lectures. His book, ‘An Appeal to the World’ (William Morrow, 2017) is a recent and good overview of his thinking.
 The Dalai Lama, ‘The Good Heart: A Buddhist Perspective on the Teachings of Jesus (Wisdom Publications, 1998).