Allah, the Mighty and Majestic, said:
﴿وَمِنْ آيَاتِهِ أَنْ خَلَقَ لَكُم مِّنْ أَنفُسِكُمْ أَزْوَاجًا لِّتَسْكُنُوا إِلَيْهَا وَجَعَلَ بَيْنَكُم مَّوَدَّةً وَرَحْمَةً ۚ إِنَّ فِي ذَٰلِكَ لَآيَاتٍ لِّقَوْمٍ يَتَفَكَّرُونَ﴾ “And among His Signs is this, that He created for you wives from among yourselves, that you may find repose in them, and He has put between you affection and mercy. Verily, in that are indeed signs for a people who reflect.” (Surah Ar-Rūm 30:21)
Shaykh ʿAbd al-Raḥmān ibn Nāṣir al-Saʿdī - may Allah have mercy on him - said in the explanation of this verse:
{And among His Signs} - indicating His mercy, His care for His servants, His tremendous wisdom, and His all-encompassing knowledge - {is that He created for you wives from among yourselves}, who are suitable for you and you are suitable for them, who resemble you and you resemble them, {that you may find repose in them, and He has put between you affection and mercy}, by what He arranged through marriage of the means that bring about affection and mercy.
So through the wife there occurs enjoyment, pleasure, and benefit through the existence of children and their upbringing, and tranquility with her. Thus you will not find, in most cases, between any two people what exists between spouses of affection and mercy. {Verily, in that are indeed signs for a people who reflect} - those who employ their thoughts, contemplate the signs of Allah, and move from one matter to another.