The Maitrayaniya Upanishad, likely composed in a later century than Katha and Shvetashvatara Upanishads but before Patanjali's Yoga Sutra, mentions sixfold yoga method – breath control (pranayama), introspective withdrawal of senses (pratyahara), meditation (dhyana), mind concentration (dharana), philosophical inquiry/creative reasoning (tarka), and absorption/intense spiritual union (samadhi).
Some Christians integrate yoga and other aspects of Eastern spirituality with prayer and meditation. This has been attributed to a desire to experience God in a more complete way. In 2013, Monsignor Raffaello Martinelli, servicing Congregation for the Doctrine of the Faith, having worked for over 23 years with Cardinal Joseph Ratzinger (Pope Benedict XVI), said that for his Meditation, a Christian can learn from other religious traditions (zen, yoga, controlled respiration, Mantra), quoting Aspects of Christian meditation: "Just as "the Catholic Church rejects nothing of what is true and holy in these religions," neither should these ways be rejected out of hand simply because they are not Christian. On the contrary, one can take from them what is useful so long as the Christian conception of prayer, its logic and requirements are never obscured. It is within the context of all of this that these bits and pieces should be taken up and expressed anew." Previously, the Roman Catholic Church, and some other Christian organizations have expressed concerns and disapproval with respect to some eastern and New Age practices that include yoga and meditation.
Malaysia's top Islamic body in 2008 passed a fatwa, prohibiting Muslims from practicing yoga, saying it had elements of Hinduism and that its practice was blasphemy, therefore haraam. Some Muslims in Malaysia who had been practicing yoga for years, criticized the decision as "insulting." Sisters in Islam, a women's rights group in Malaysia, also expressed disappointment and said yoga was just a form of exercise. This fatwa is legally enforceable. However, Malaysia's prime minister clarified that yoga as physical exercise is permissible, but the chanting of religious mantras is prohibited.
Equipment required? No. You don't need any equipment because you'll rely on your own body weight for resistance. But you'll probably want to use a yoga mat to keep you from sliding around in standing poses, and to cushion you while in seated and lying positions. Other, optional equipment includes a yoga ball for balance, a yoga block or two, and straps to help you reach for your feet or link your hands behind your back.