Intention (نیت): Intention is the firm plan of the Heart. It is a consciousness of purpose in the mind. As per Shariat it refers to the intention to perform any deed for the sake of Allah (جل جلاله). Intention (to make Niyyat) is an integral part of all actions. There are certain deeds (Ibaadat) where Intention is a prerequisite for its validity e.g Salat. And there are certain deeds (Ibaadat) where Intention is not necessary e.g Wudu (Ablution) but without Intention (Niyyat) an action is void of Thawaab (Reward).
Niyyah (Intention) and Ikhlas (sincerity) form the basis of every action that we do in our lives.
It is based on these that our actions shall be accepted or rejected by Allah (جل جلاله). If this is not in place, then every act you do is a waste for our Akhirah. How would we feel when, even after doing lots of good deeds in this life, on the Day of Judgement we are among the losers? What if every good deed and every Ibadat we do is considered a waste near Allah (جل جلاله)?
This is precisely why one needs to learn about Niyyah (Intention) and Ikhlas (sincerity) so that our good deeds are recorded properly and we get benefit out of it in Akhirah. This is the first lesson that every Muslim should learn when seeking knowledge.
:قَالَ اللهُ تَعَالَى
" لَنْ يَنَالَ اللَّهَ لُحُومُهَا وَلا دِمَاؤُهَا وَلَكِنْ يَنَالُهُ التَّقْوَى مِنْكُمْ "
Allah, the Exalted, says: "It is neither their meat nor their blood that reaches Allah, but it is piety from you that reaches Him." (22:37)
:قَالَ رَسُولَ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ
"إِنَّمَا الأَعْمَالُ بِالنِّيَّاتِ"
"رَوَاهُ البُخَارِيُّ وَمُسْلِمٌ "
Prophet, sallallahu ‘alayhi wasallam, said :"Actions will be judged according to the intentions (behind them)"