What does it mean to say that affirming a divine attribute dictates negation of its opposite?

Firstly:

When Allah
states that He is free of an attribute, that negation implies two things:

i.        This
attribute is not one of His attributes

ii.       Its
opposite is to be affirmed in the most perfect manner.

Allah, may He be
exalted, says (interpretation of the meaning):

“and
your Lord treats no one with injustice”

[al-Kahf 18:49].

In this verse,
the attribute of injustice or wrongdoing is negated in the case of Allah; at
the same time it is an affirmation of its opposite in the most perfect
manner. Thus Allah, may He be glorified, does not do any injustice, because
of His perfect justice.

The reason for
the affirmation in a perfect manner of the opposite of the negated attribute
is that negation of an attribute without affirmation of its opposite is
nothing, and does not imply perfection. Allah, may He be exalted, does not
ascribe to Himself anything that does not imply perfection.

Shaykh al-Islam
Ibn Taymiyah (may Allah have mercy on him) said:

It should be
understood that negation of an attribute does not imply praise or perfection
unless it implies an affirmation (of its opposite). Otherwise, mere negation
does not convey any sense of praise or perfection, because negation that
does not imply something is just nothing, and if it is nothing, it does not
mean anything. So, as the saying goes, it is not anything, let alone being
praise or perfection. Because negation is something that may be applied to
something that does not exist, that which does not exist cannot be described
in any sense of praise or perfection.

Most of the
attributes that Allah negates with regard to Himself imply affirmation of a
positive attribute, such as when He says (interpretation of the meaning):

“Allah!
La ilaha illa Huwa (none has the right to be worshipped but He), the Ever
Living, the One Who sustains and protects all that exists. Neither slumber,
nor sleep overtake Him… His Kursee extends over the heavens and the earth,
and He feels no fatigue in guarding and preserving them”

[al-Baqarah
2:255].

Negation of
slumber and sleep implies life and sustaining in the most perfect sense.
Thus it highlights the perfect attributes of the Ever Living, the One Who
sustains and protects all that exists. Similarly, His words ‘and
He feels no fatigue in guarding and preserving them”
mean that it is not too bothersome or too burdensome for Him, which implies
the perfect nature of His power, in contrast to any created being that has
power, for that created being will only be able to do something with some
difficulty and effort, which is a reflection of the imperfection and
shortcomings of his power. Similarly, in the verse (interpretation of the
meaning):

“not
even the weight of an atom (or a small ant) or less than that or greater,
escapes from His Knowledge in the heavens or in the earth”

[Saba’ 34:3],

negation of even
an atom’s weight escaping His knowledge implies that He has knowledge of
every atom in the heavens and on earth, and so on.

End quote from
Majmoo‘ al-Fataawa, 3/35, 36

Shaykh Ibn
‘Uthaymeen (may Allah have mercy on him) said:

Whenever Allah,
may He be exalted, negates something with regard to Himself, what is meant
is that He does not have that attribute, but it is affirming the opposite
attribute in a perfect sense. Negation in this regard is not a negation with
no implication, because negation does not indicate perfection unless it
implies some perfect attribute. That is because negation is non-existence,
and non-existence is nothing, let alone perfection. Moreover, negation may
be because of the lack of connection, so it is not perfection, such as if
you say: The wall does not wrong anybody, but it has no ability to do that
deed, so in that case, negation implies a shortcoming.

End quote from
al-Qawaa‘id al-Muthla fi Sifaat Allaah wa Asmaa’ihi al-Husna (p. 23).

See also:
Taqreeb at-Tadmuriyyah by Shaykh Ibn ‘Uthaymeen (may Allah have mercy on
him) (p. 47-50).

Secondly:

The positive
attributes that Allah has affirmed with regard to Himself imply two things:
affirmation of the divine attribute and negation of the opposite of that
which is affirmed with regard to Him, may He be glorified.

Shaykh al-Islam
Ibn Taymiyah (may Allah have mercy on him) said:

The Muslim
should affirm that which must be confirmed for Allah of attributes of
perfection, and he must negate that which must be negated with regard to Him
of the opposite of those attributes.

End quote from
at-Tadmuriyyah (p. 4).

He also said:…
The religious texts affirm those divine names and perfect attributes that
have been narrated, and whatever is opposite to that, the religious texts
negate it, as they negate the notion that He has any equal or peer.
Affirmation of a thing is the negation of its opposite, and whatever may be
connected to its opposite.

End quote from
Majmoo‘ al-Fataawa (3/84).

Shaykh Yoosuf
al-Ghufays (may Allah have mercy on him) said: The basic principle in this
regard is that every text that affirms an attribute implies that the
attribute is to be affirmed and indicates that Allah is to be declared to be
above the opposite. Declaring Allah to be above all shortcomings is of two
types:

1.    

Declaring Him to
be above all shortcomings in general terms

2.    

Declaring Him to
be above all shortcomings in specific terms.

With regard to
the texts that affirm the divine attributes, they are declaring Him to be
above all that is not befitting to Him in general terms.

With regard to
declaring Him to be above all shortcomings in specific terms, that is
appropriate with reference to a specific attribute. In other words, when
Allah says (interpretation of the meaning): “And
He is the All-Knower of every thing”
[al-Hadeed 57:3],
that indicates that He is above being ignorant. The verse implies this
specific sense of His being above all shortcomings. Moreover, it includes
declaring Him to be above shortcomings in general terms, for the One Who has
knowledge of all things must be the First, and He must be the Last, and He
must be the Lord, and so on…

Every text that
affirms any divine attribute implies negation of any similarity or
resemblance (of that divine attribute to the attributes of His creation); it
implies that He is above having any shortcomings in a specific sense and
that He is above having any shortcomings in general terms.

End quote from
Sharh at-Tadmuriyyah.

Conclusion:

Based on the above, what Allah, may He be exalted, affirms for Himself of
attributes, we must affirm that attribute, and negate what is opposite to it
of shortcomings.

And Allah knows best.