In The Name of Allaah, The Most Merciful, The Bestower of Mercy.

The Messenger of Allaah [sallal-laahu-alayhi-wasallam] said, “Indeed Allaah is Pure and He does not accept, except that which is pure”.

In this hadith, he [sallal-laahu-alayhi-wasallam] described Allaah [جل وعلا] that He [سبحانه] is Pure.  He [سبحانه] is Pure, meaning free from all imperfections and deficiencies.  He is Pure in His Essence, in His Names and Attributes, and in His Commandments and Prohibitions.  He [سبحانه] is Pure in every aspect and imperfection cannot reach Him; and for that reason He does not accept actions, statements and intentions except that which is pure.  He does not accept filthy statements, actions and intentions. He does not accept except the pure, as He [The Exalted] said: [إِلَيۡهِ يَصۡعَدُ ٱلۡكَلِمُ ٱلطَّيِّبُ – ‘To Him ascend (all) the goodly words][Surah Faatir Ayah:10]

He [سبحانه] does not accept, except good speech and good actions; as for filthy speech, then indeed Allaah rejects and hates it, such as lies, backbiting, tale carrying, abuse, false speech and false testimony; and all filthy statements; [such as] shirk and kufr.  All of this is filthy speech and does not ascend to Allaah, and is not accepted.

[Source: An Excerpt from ‘Al Minhatu Ar-Rabbaaniyyah Fee Sharh Arba-een Nawawiyyah’ page:133-134: by Shaikh Saaleh Al-Fawzaan (hafidhahullaah). Slightly paraphrased]