Ibn Al-Qayyim (rahimahullah) said:

"The year is a tree.

And the months are its branches.

And the days are its twigs.

And the hours are its leaves.

And the breathing is its fruit.

So the one whose respiration is in obedience: then the fruit of his tree will be good; and the one whose case is in sinfulness: then his fruit will be colocynth (a type of bitter plant). And indeed the reaping will be on The Day of Return.

And it is at the reaping wherein the sweet form of the fruit will become distinct from its bitter.

Ikhlaas (sincerity) and Tawheed are a tree in the heart; and their branches are the actions; and their fruit is: a well-disposed life in the dunya – as well as everlasting bliss in the Hereafter.

Just as the fruit of Paradise is not cut off (due to season) nor is it out of reach;[1]accordingly the fruit of Tawheed and Ikhlaas in the dunya are likewise.

Shirk and lying and riyaa [2] are a tree in the heart; and their fruit in the dunya is: fear and anxiety and sorrow and a constricted chest and a darkness of the heart.

And their fruit in the Hereafter is: Az-Zaqqoom [3] and an everlasting punishment.

Indeed – Allaah has mentioned both of these two trees in Soorah Ibraheem. [4]”

(Taken from: Al-Fawaa-id p.261)

[1] A reference to His saying The Most High:

{وَفَاكِهَةٍ كَثِيرَةٍ. لّا مَقْطُوعَةٍ وَلا مَمْنُوعَةٍ}

((And an abundance of fruit. Neither limited [to season] nor forbidden.)) (Al-Waaqi’ah: 32-33)

[2] Al-Jurjaanee said riyaa is: “abandoning Ikhlaas in actions due to observing other than Allaah in that.” Ibn Hajar stated: “riyaa is manifesting worship with the intent that the people should see it and so they praise its performer.” (See: Nadratun Na’eem vol 10 p.4552)

[3] As He, The Most High states:

{إِنَّ شَجَرَةَ الزَّقُّومِ طَعَامُ الأثِيمِ}

((Indeed the tree of Az-Zaqqoom. Will be the food of the sinners.)) (Ad-Dukhaan: 43-44)

[4] That is in His saying The Most High:

{أَلَمْ تَرَى كَيْفَ ضَرَبَ اللَّهُ مَثَلًا كَلِمَةً طَيِّبَةً كَشَجَرَةٍ طَيِّبَةٍ أَصْلُهَا ثَابِتٌ وَفَرْعُهَا فِي السَّمَاءِ }

 {تُؤْتِي أُكُلَهَا كُلَّ حِينٍ بِإِذْنِ رَبِّهَا وَيَضْرِبُ اللَّهُ الأَمْثَالَ لِلنَّاسِ لَعَلَّهُمْ يَتَذَكَّرُونَ}

{وَمَثَلُ كَلِمَةٍ خَبِيثَةٍ كَشَجَرَةٍ خَبِيثَةٍ اجْتُثَّتْ مِنْ فَوْقِ الأَرْضِ مَا لَهَا مِنْ قَرَارٍ}

((Do you not see how Allaah sets forth a parable; a good word – the like of a good tree, whose root is firmly fixed and its branches (reach) to the sky. It produces its fruit all the time, by permission of its Lord, and Allaah sets forth parables for mankind in order that they may remember. And the parable of a bad word is the like of a bad tree; uprooted from the surface of the earth having no stability.)) (Ibraheem: 24-26)