In simple terms, mediation or Tawassul is anything which becomes a means to gain nearness to Allah. In its general Islamic meaning, everything which takes us near Our Lord is mediation. Therefore all good deeds such as faith in Allah and the Prophet (peace be upon them), prayers, fasting, Hajj, and other deeds serve as mediators that draw us nearer to Allah. Dr. 'Abd al-Karim bi-Azar Shirazi defines Tawassul in following words: "The lexical meaning of Tawassul is 'nearness' or a 'means' through which to reach a certain goal. For instance, when it is said 'wa wassala ila Allah', it means to perform a certain act for gaining proximity to God. Accordingly Wasil here means being 'desirous of God'.
"According to the prominent Sunni scholar, Sayyid Muhammad Alusi al-Baghdadi, Wasila is a means of imploring in order to gain nearness to God through good deeds and abstaining from sins. For example when it is said "wasala ila kadha", it means a thing through which nearness is gained." (Message of Thaqalayn, v. 5 no. 4)
In his most beautiful and eloquent expression, the Commander of the Faithful Imam Ali (peace be upon him) admonishes us to gain "mediation or Tawassul" through the following means:
"The best means by which seekers of nearness to Allah, the Glorified, the Exalted, seek nearness, is the belief in Him and His Prophet, fighting in His cause – for it is the high pinnacle of Islam – and (to believe) in the Kalimaatul-Ikhlas (the expression of Divine purification) for it is just nature, and the establishment of prayer for it is (the basis of) community, payment of Zakaat (Islamic tax) for it is a compulsory obligation, fasting for the month of Ramadan for it is the shield against chastisement, the performance of Hajj of the House of Allah and its Umrah (other than annual visit) for these two acts banish poverty and wash away sins, regard for kinship for it increases wealth and length of life, to give alms secretly for it covers shortcomings, giving alms openly for it protects against a bad death, and extending benefits (to people) for it saves from positions of disgrace.
Go ahead with the remembrance of Allah for it is the best remembrance, and long for that which He has promised to the pious, for His promise is the most true promise. Tread the course of the Prophet for it is the most distinguished course. Follow the sunnah of the Prophet for it is the most right of all behaviours. Learn the Qur'an for it is the fairest of discourses and understand it thoroughly for it is the best blossoming of hearts. Seek cure with its light for it is the cure for hearts..." (Sermon 109, Nahj al-Balagha)
He also states in saying 135: "Daily prayers are the best medium through which one can Seek the nearness to Allah."
In the Holy Qur'an (5:35), it says: "O you who believe! be careful of (your duty to) Allah and seek means of nearness to Him and strive hard in His way that you may be successful." The scholars in exegesis to the above verse of holy Qur'an say that the mediation from Prophets, Imams or the righteous servants of Allah is included in the meaning of mediation. Allama Tabatabai discusses the verse in Al-Mizan in the following words:
"Al-Qummi has written about the words of Allah: 'O you who believe! Fear Allah and seek means of nearness to Him...' that (the Imam) said, 'Come near Allah through the Imam'... That is, through obedience to the Imam. Thus it is based on the flow of the Qur'an, and applies the verse to its best import... The Leader of the Faithful said about the Divine Word 'and seek means of nearness to Him': 'I am the means of nearness to Him'."
In a lengthy narration known as the Hadith of Wasila, the Prophet is reported to have said, "When you ask from Allah, ask for me the Wasila... It is my rank in the Garden..."
Upon reflection, we can realize how ther verse from the Qur'an fits with the narrations. As Allama Tabatabai further states: "[we] will find that Wasila is the position of the Prophet in the presence of his Lord, with which he gets nearer to Allah; and joins him there his pure progeny, then the good servants from among his Ummah. It has also been narrated in some traditions from them that verily the Messenger of Allah adheres to his Lord, and we adhere to him and you (the Shi'as) adhere to us."
Let us conclude our discussion on mediation by praying to Almighty Allah saying the prayer taught by Imam as-Sajjad (peace be upon him) on mediation:
My God, I have no mediation with Thee but the tender acts of Thy clemency, nor any way to come to Thee but the gentle favors of Thy mercy and the intercession of Thy Prophet, the prophet of mercy, who rescued the community from confusion. Make these two my tie to attaining Thy forgiveness and let them take me to triumph through Thy good pleasure! My hope has dismounted in the sacred precinct of Thy generosity, my craving has alighted in the courtyard of Thy munificence. So actualize my expectation from Thee, seal my works with good, and place me among Thy selected friends, those whom Thou hast set down in the midst of Thy Garden, and settled in the abode of Thy honor, whose eyes Thou hast gladdened by gazing upon Thee on the day of meeting Thee, and whom Thou hast made heirs to the sure stations in Thy neighborhood!
O He none more generous than whom is reached by the reachers and none more merciful than whom is found by the aimers! O Best of those with whom the lonely are alone, O Tenderest of those with whom outcasts seek haven! Toward the expanse of Thy pardon have I extended my hand, upon the skirt of Thy generosity have I fastened my grasp! Show me no deprivation and afflict me not with disappointment and loss! O Hearer of supplications! O Most Merciful of the merciful!"
(The Whispered Prayer of Those Asking for Mediation, Sahifa Sajjadiyya)