But, as in the case of the prophzts, all the abovementioned qualifications are not enough to automatically make one an Imam. Imamat is not an acquired job; it is a 'designation'. bestowed by Allah.
It is for this reason that the Shia Ithna'asheris believe that it is only Allah who can appoint a successor to the Prophet; that the Ummah have no choice in this matter: their only duty is to follow such divinely appointed Imam or Caliph.
The Sunnis, on the other hand, believe that it is the duty of the Ummah to choose a Caliph.
A) AYATS OF QURAN
The following Ayats or verses of the Quran confirm the view held by the Shias:
1) "And Thy Lord Creates what He wills, and chooses;
They have no right to choose."
QURAN: 28 :68
It clearly shows that man has no right to make any selection; it lies entirely in the hands of Allah.
2) Before creating Prophet Adam(as), Allah informed the angels:
"Verily, I am about to make a Caliph on the earth."
QURAN: 2: 30
And when the angels protested in a guarded way against the scheme, their protest was brushed aside by a curt reply,
"I know what ye know not."
QURAN: 2: 30
If the MA'SOUM or Infallible angles were given no say in the appointment of a Caliph. Then how can non-ma'soum humans expect to take the whole authority of such appointment in their own hands?
3) Allah himself appointed Prophet Dawood(as) as the Caliph on the earth:
"O Dawood! Verily, We have made thee (our) caliph on earth."
QURAN: 38 :26
See, how everywhere Allah attributes the appointment of the Caliph or Imam exclusively to Himself.
4) Likewise, the call went to Prophet Ibraheem(as):
"I am about to make thee an Imam to mankind."
QURAN: 2: 124
5) Then as a general rule, it is stated:
"And We made them Imams who were to guide by our Command."
QURAN: 21: 73
6) When the Prophet Musa(as) wanted a Wazier to help him in his responsibilities, he did not appoint someone by his authority. He prayed to Allah:
"And make for me a Wazier from among my family, Aaron my brother."
QURAN: 20: 29-30
And God said:
"Granted is thy prayer, O Musa!"
QURAN 20: 36
The universal practice of previous prophets had been to nominate (on command of Allah) his successor without any interference from the Ummah.
The history of the previous prophets does not offer a single instance in which a Prophet's successor would have been elected by a voting of his followers.
There is no reason why in the case of the successors of the Last Prophet this established Divine Law should suffer any change. Allah says:
"And thou shalt never find a change in Divine Practice."
QURAN 33: 62
C) LOGICAL REASON
1) The same reasons which prove that the appointment of a prophet was a Divine function, prove with equal force that the successor of that prophet also should be appointed by Allah. The Imam or Cahiph, like the Prophet, is appointed to carry on the work of Allah; he must be responsible to Allah. If he is appointed by people, his first loyalty will be not for the Allah, but for the people who would be 'the basis of his authority.' He always will try to please people, because if they were to withdraw their confidence in him he would lose his job. So he will not discharge the duties of religion without fear of favour; his eyes will always be on political considerations. Thus the work of God will suffer.
And the history of lslam provides ample evidence of glaring disregard to the tenets of religion practised by the man-made caliphs right from the begining. So, this argument is not just academic; it has a mass of solid historical evidence behind it.
2) Also, it is only Allah who knows the inner feelings and thoughts of a man; no other man can ever know the true nature of his fellow. May be someone is posing as a pious and God fearing man just to impress his colleagues, so that he may gain some worldly benefit. Such examples are not rare in the history. Take, for example, the case of AbdulMalik bin Marwan who used to spend all his time in the mosque in prayer and recitation of the Quran. He was reciting the Quran when news reached him of the death of his father and that the people were waiting to pledge their allegience to him; he closed the Quran and said: "This is the parting between me and thee."
Therefore, as the existence of qualifications which are necessary for an Imam or Caliph can truly be known only to Allah and, therefore, it is only Allah who can appoint an Imam or Caliph.