And We shall turn to whatever actions they did and make them into scattered dust[2]
He also said (which means):
It is he who created life and death to see which of you is best in action[3]
Therefore, know before everything else the necessary conditions for actions before they are accepted. It is vital that two great and important matters are fulfilled for every action. If they are not the action will not be accepted.
The First: That the one who performed the
action desired nothing but the Face of Allaah 
by it.
The Second: That the action is in agreement
with what Allaah the Exalted has legislated in His Book or His Messenger
has explained in his sunnah.
Fudayl ibn Ayyaad, a taabi'ee, said regarding the verse {...that He may test you, which of you is best in deeds...} [11:7], "The most sincere and the most correct" so those who were around him said "And what is the most sincere and the most correct?" He replied "Action, if it is correct but not sincere will not be accepted and action, if it is sincere but not correct will not be accepted until it is both sincere and correct. Sincere means that nothing but the Face of Allaah is sought and correct means that it is in conformity with the Sunnah."
And some of the Salaf used to say: There is no action, even if it is insignificant , except that it will have two questions put to it: Why did you do it? and: How did you do it?
The first question is about the reason for the action and its motive. If the motive was for an objective from among the objectives of the world such as seeking praise or status or any other worldly aim, it is an evil action and will be thrown back at its performer. If the motive for the action was to fulfil the right of Allaah of pure enslavement to Him and seeking a means of nearness to Him then it is a good action and will be accepted inshaa'allaah.
The second question is about the following and
imitation of the Messenger .
Was the action from amongst the legislated actions or was it from your
innovation and invention? If it was from the guidance of the Messenger
then it is a good action and if it was in opposition to the practise of
the Messenger then it is an
evil action and will not be accepted from its performer as is proven in
the hadeeth of Aa'ishah 
who
said: The Messenger of Allaah
said (which means): "Whoever introduces into this affair of ours something
that does not belong to it will have it rejected."[4]
And she also reports that
the Messenger of Allaah said:
"Whoever does an action which we have not commanded will have it rejected."[5]
When one of the above two conditions is not fulfilled the action is neither righteous nor acceptable. The saying of the Blessed and Exalted provides evidence for this (which means):
"And whoever places his hope in the meeting with His Lord let him work righteous deeds and in the worship of His Lord, associate none as a partner."[6]
Allaah, the Sublime has commanded in this verse that the action should be righteous meaning, agreement with the Sharee'ah. Then He commanded that the person should make it sincerely for Allaah, desiring by it nothing besides Him.
Al-Haafidh Ibn Katheer (rh) said: These are the
two pillars of the accepted action. It is necessary that the action is
sincerely for Allaah and also correct, upon the Sharee'ah of the Messenger
of Allaah . The likes of this
has also been reported from al-Qaadi Ayyaad - may Allaah have mercy upon
Him - and others.
Allaah the Exalted also said (which means):
And who is better in religion than the one who submits his face to Allaah and is a doer of good?[7]
The meaning of submitting ones face for Allaah
is: Making one's intention and action for Allaah, and the meaning of doing
good is: Imitating and following the Messenger's
Sunnah.
Footnotes
1 This is illustrated in his (sas) saying: "Perhaps a fasting person obtains nothing from his fasting but hunger and one who stands during the night in prayer nothing but tiredness." Reported by Ibn Maajah from Abu Hurairah and Shaikh Al-Albaanee declared it to be authentic in his Saheeh ul-Jaami', no. 3482.
