The purpose of mantras is to protect the mind. "Manas" means the mind and "Tra" means to protect. From our minds our world (and our karma) is created. To uncreate negative thought patterns it's very helpful to practice reciting mantras. Just like types of music changes our mood and our thoughts, mantras do the same, perhaps more directly and powerfully. The use of mantras, like the practice of yoga, is one of many gifts of India that have made its way into the West.
In the article, Spiritual Practices as a Remedial Measure, I shared a story that K.N. Rao writes about in his excellent book, Yogis, Destiny and the Wheel of Time, that demonstrates the amazing power of reciting mantras for a specific time period. This story involves the hymn called the Rama Raksha Stotra that has been praised by famous astrologers in India as a remedial measure. Spiritual practices of any tradition will have value as a remedial measure, it doesn't need to be from the Hindu tradition. Here is the translation of that mantra with links to an audio version, Sanskrit version, and English transliterated version.
Thus begins the hymn of Lord Ram for protection:
OM, Salutations to Lord Ganesh.
(Note - Every mantra has a deity, shakti and central point in addition to its author, meter and type of usage.)
The author of this hymn is Buddhakaushika. The deity is Sri Sita-Ramachandra. The metre is anushtup. The power is Sita, central point is Hanuman, and the usage is recitation.
Thus begins the dhyana (meditation) of this mantra. One should meditate on Rama who has arms reaching his knees, who is holding a bow and arrow, who is seated in a lotus position, who is wearing yellow clothes, whose eyes compete with petals of a fresh lotus, who looks satisfied, whose eyes are fixed on the lotus-like face of Sita sitting in his left lap, whose color is like that of rain cloud, who has adorned different jewelery, who is wearing hair reaching up to his thighs.
The life story of Sri Rama has a vast expanse and each and every letter of it is capable of destroying even the greatest sins of mankind.
Let us meditate on the lotus-eyed, dark-complexioned Rama who is well-adorned with a crown of hair and has Sita and Lakshmana by his side.
Let us meditate on Rama who has a sword in a receptacle and bow and arrows, who destroyed the demons, who is not born but is incarnated to protect the world with his actions. May the learned read the Rama Raksha Stotram, which destroys all sins and grants all desires.
(Begin listing details of the body to be protected)
May Rama who is Raghu's descendant protect my head. May Rama who is Dasharatha's son protect my forehead.
May the lord Rama who is Kausalya's son, protect my eyes. May Rama who is the favorite of Vishvamitra protect my ears. May Rama who is the savior of yagya protect my nose. May Rama who is affectionate to Lakshmana protect my mouth.
May the Rama who is a sea of knowledge protect my tongue. May Rama who is saluted by Bharata protect my neck. May Rama who holds divine weapons protect my two shoulders. May Rama who broke Shiva's bow protect my two upper arms.
May the Rama who is the husband of Sita protect my two hands. May Rama who conquered Parashurama protect my heart.
May Rama who killed the rakshasa named Khara protect my abdomen. May Rama who gave refuge to Jambavad protect my navel.
May Rama who is master of SugrIva protect my waist. May Rama who is master of Hanuman protect my two hips. May Rama who is the best of Raghus and who destroyed the lineage of Rakshasas (demons) protect my two thighs.
May Rama who built the bridge protect my two knees. May Rama who killed the ten faced demons protect my two shins. May Rama who gave wealth to Vibhishan protect my two feet. Thus may Rama protect my entire body.
May the good man who reads this 'stotra', which has all the power of Rama, be blessed with long life, happiness, children, success and humility.
No one who is wandering below the earth or on the earth or above the earth or those who wander surreptitiously changing their forms, will even be able to see the man protected by the name of Rama, let alone bring any harm to him.
No sin can attach to the man who singeth the praise of the lord and he will prosper in this world and get salvation.
One who wears this mantra of Rama Nama (the name of Rama) around his neck will have all powers at his beck and call.
He who wears this armour called vajrapanjara will be unscathed and will win victory everywhere.
Buddhakaushika was commanded in his dream by Lord Shiva to compose this hymn, and he did so as soon as he awoke in the morning.
Rama, who grants all desires, removes all obstacles and is the praise of all three worlds is our 'Lord' indeed.
May the two brothers ever protect us, who are young, handsome, lotus-eyed and bark and deer-skin dressed.
May these two sons of Dasharatha, the two scions of Raghu, the brothers Rama and Lakshmana, the ones who are subsisting on roots and fruits and practicing penance and celibacy, protect us. May they who are the foremost among the archers, the destroyers of the demons and the refuge of all beings, protect us.
Rama and Lakshmana, their bows pulled and ready, their hands on the arrows packed in ever full quivers carried on their backs, may they always escort me in my path, for my protection.
Ever prepared and armed with sword, shield, bows and arrows and
followed by Lakshmana, Rama is like our cherished thoughts come to life. May he, along with Lakshman, protect us.
Rama, the scion of Raghu and the son of Dasaratha and Kausalya, and ever accompanied by Lakshmana, is all powerful and is the perfect man.
Rama is perceived through Vedanta. He is lord of all yagya, ancient and the best man, beloved of Janaki, whose bravery is immeasurable.
Lord Shiva says, "my devotee who recites these names of Rama with faith, will attain more religious merit than one obtainable by other sacrifices. There is no doubt about it."
Those who sing the praise of Rama, who is lotus-eyed, dark-complexioned and dressed in yellow clothes, through this hymn are no longer ordinary men trapped in the world. They become liberated.
I salute that Rama who is handsome, the elder brother of Lakshmana, the husband of Sita and the best of the scions of the Raghu race, who is the ocean of compassion, the stockpile of virtues, the beloved of the Brahmans, the protector of Dharma, who practises the Truth, the Lord emperor of kings, the son of Dasaratha, dark-complexioned, the personification of Peace and tranquillity, the enemy of Ravana, the crown jewel of the Raghu dynasty and the cynosure (north star) of all eyes.
I salute that Rama who is benevolent and cool as the Moon, and who is the lord of Sita and the master guardian of all.
I surrender to that Rama who is the delight of the Raghus, elder brother of Bharata and the tormentor of his enemies in the war.
I remember the two feet of Rama in my mind, I praise them by my speech, I bow to them with my head, I take resort in them!
Rama is like my mother, father, master and friend, indeed the kind-hearted Rama is all I have. I know of no other like him, I really don't!
I salute that Rama who has Lakshmana on his right and Sita on the left and who has Hanuman in his front.
I take refuge in that Rama who is quite pleasing to the sight, the master of the stage of war, lotus-eyed, lord of the Raghu race and compassion-personified.
I take refuge in the Lord Hanuman who is as fast as the mind, equals his father, the wind-God, in speed, is the master of the senses, the foremost amongst the learned, the leader of the Monkey forces and the great messenger of Sri Rama.
I salute the great sage Valmiki who sings the glorious name of Rama resorting to his Ramayana as sweetly as a cuckoo will sing sitting atop a tree.
I bow again and again to Rama who removes all obstacles and
grants all wealth and pleases all.
The roar of the name of Rama is the destruction of the cause of rebirth (hence the cause of liberation), generates wealth and scares Yama's (death's) messengers.
I worship Rama, the jewel among the kings, through whom the hordes of demons have been destroyed. Beyond Him there is nothing to be worshipped. I am His servant, my mind is totally absorbed in Him. O Rama, please lift me up. This verse gives all the seven declensions of the singular word Rama and gives one way of remembering them!
O fair-faced Parvati! I enjoy saying Rama Rama. Uttering but once the name of 'Rama' is equal to the uttering of any other name of God, a thousand times.