Why Kalima of Muslims is not mentioned in the Quran and in what sense is Quran complete ?
The Kalma of Muslims is that “There is no God but Allah and Muhammad is the messenger of Allah”. However, in Quran at several places, Allah says that whoever believes in Allah and the Last Day will be successful in the Hereafter. Then why does our Kalma not comprise of these two vital aspects? And related to this question is, that what is the minimum criteria (in beliefs) for salvation?
And my second question is that we say Quran is a complete book, and the Quran says it itself also, ‘Nothing have we omitted from the book’. But in what sense is it a complete book, ‘Explaining all things’, because it does not even contain directions as to how to worship Allah?
Most statements humans make assume implications that are not explicitly mentioned. “Cricket is my favourite sport” is a statement that by implication includes “if played in the right spirit;” “potato is my favourite vegetable” clearly implies “if properly cooked”, even if it is not explicitly mentioned in the statement. If we start demanding all implications of a statement to always be expressed explicitly, we will end up with unbearably long communications. Therefore intelligent humans have settled for an arrangement which entails that we make a statement that should give an understanding in principle and the receivers of it should then proceed to unravel the natural implications of it. Quite often a brief statement is expressed in a particular way, and not in some other form, simply because the context demands that aspect — and not all aspects of it — to be expressed.
The Quran in the statement of your first question is doing just that. When it says that beliefs in Allah and the hereafter are sufficient for success in the next life, it implies that one should believe in everything Allah has done to run the affairs of this world the information of which has come to us through sources that cannot be denied, like he sent prophets to guide humans. At times it is justifiable to say that belief in Allah is enough for salvation, like the Quran has done in this statement: “Indeed those who say ‘Our Lord is Allah’ and then stick to it, we send down angels on them.” (41:30) In the above-quoted verse even though faith in the hereafter has also not been mentioned, God’s full approval of the approach adopted by the individual who properly believes in Allah has been promised. This has been done because it is implied that the mention of proper belief in Allah presumes belief in the hereafter as well.
What is mentioned in our Kalima is the expression of the same reality in another form. In the Kalima, we don’t find the mention of belief in the hereafter, because the mention of belief in Allah takes care of it.
A similar rule of communication applies to your other question. At times we make a generalised statement but we mean by it only a particular understanding. When I say to my son “I looked for you everywhere”, I don’t mean that I looked for him in the entire planet, although somebody unaware of this principle of communication might foolishly insist that I told a lie because I never looked for my son in the entire planet. Likewise, when the Quran says “Nothing have we omitted from the book”, it only means that God hasn’t omitted any important information that was needed for guidance for the people who were the immediate addressees of the Quran. It doesn’t mean that God hasn’t ommitted any piece of information from being mentioned in the Quran. The latter claim cannot be satisfied by any book no matter how large the volume of it may be.