يَا بَنِي آدَمَ خُذُوا زِينَتَكُمْ عِنْدَ كُلِّ مَسْجِدٍ
Yā banī Ādama khudhū zīnatakum ‘inda kulli masjid
O Children of Adam! Put on your adornment on every occasion of prayer
(Sūratul A‘rāf, No. 7, Āyat 31)
Salāt is a private conversation between the believer and Allah. It is a meeting, a meeting of one who is lowly and insignificant, with One who is Mighty and all Powerful. Thus it is incumbent on the lowly slave to try hard to be presentable so that he may be accepted into the presence of his Mighty Lord.
During Salāt the believer should put on his most beautiful adornment. Just as he would take great care of his appearance when meeting someone important in this world, the believer is particular about how he goes to meet his Lord. This includes brushing teeth, combing the hair, putting on clean clothes, using perfume, and generally being pleasantly presentable. There are several Hadiths recommending these practices and the rewards for following them.
Paying attention to your appearance for Salāt shows an awe and respect for God, and an appreciation of the importance of worship. Islam emphasizes good clothing at the place and time of prayer. It helps a person feel good and increases pleasure in the Salāt. When praying with others, this type of attention also helps makes others feel better, and strengthens the bonds of believers as they pray together.
It is narrated that Imam al-Hasan (a) used to wear his best clothing for Salāt. When he was asked by others, he replied ‘Allah is Beautiful, and loves beauty. Therefore I decorate myself for Him. Then, he would recite the above verse.
Āyatullah Nāsir Makārim Shirāzī in Tafsīr-e Namūne says that although this verse was revealed in specific reference to those who performed the Tawāf of the Ka‘bah without any clothes, and those who went to the mosque in scruffy and smelly clothes, the verse still applies to all people throughout times, reminding them of the importance of good apparel for Salāt. It does not mean you should have new or fancy clothes, just clean and scented to enhance spirituality. He says the verse also refers to spiritual adornment such as sincerity, spirituality, concentration on Allah, etc.
Take care of yourself when preparing for Salāt. You will see the difference in the quality of your Salāt.
Sources: Āytaullāh Nāsir Makārim Shirāzī (ed)