Answer
Assalamo Alaikom Dear Arshad,
Thank you for your question and for contacting Ask About Islam
Of course, Allah the Almighty has no end or beginning. Allah, Most High, is absolute and not bound by anything or any limit whatsoever. This applies to both His entity and His attributes, including His existence.
So He Most High is infinite, eternal and limitless, and His perfections have no number, limit or end. The Quran says:
{He is the Ever-First, the Ever-Last, the All-Outward, and the All-Inward. He has full knowledge of everything.} (Al-Hadid 57: 3)
As for the blessings and joy in Paradise, they are eternal. Blessed inhabitants of Paradise will be favored by the eternal life.
The Quran says what means:
{But those who have faith and work righteousness, they are companions of the Garden, abiding in it eternally.} (Al-Baqarah 2: 82)
Also:
{Their Lord gives them glad tidings of a mercy from Himself and good pleasure and of gardens for them wherein is lasting enjoyment.} (At-Tawbah 9:21)
Moreover, Abu Hurayrah reported that Allah’s Messenger (peace and blessings of Allah be upon him) said:
“He who gets into Paradise [will be made to enjoy such an everlasting] bliss that he will neither become destitute nor will his clothes wear out nor will his youthfulness decline.” (Muslim)
The above Quranic verses and hadith indicate that blessings and joy in Paradise are everlasting. Inhabitants of Paradise will eternally enjoy its blessings by the grace and will of Allah.
The Quran and the Sunnah are very clear in proving the fact that Paradise is Allah’s favor and reward for the good believers who maintain true faith and act accordingly.
And Allah Almighty knows best.
I hope this helps answer your question.
Salam and please keep in touch.