And His words: “So pray to your Lord and offer sacrifice.” (Surah al-Kawthar, 2)
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“Pray to your Lord”: that is, to none besides Him.

“Offer sacrifice”: meaning, slaughter.

Overall meaning of the verse: Allah commands His Prophet ﷺ to devote both his prayer and his sacrifice exclusively to Him, in clear contrast to the polytheists who worship others besides Allah and slaughter for their idols.

Relevance of the verse to the chapter: slaughter is an act of worship that must be directed solely to Allah; to offer it to anyone else is major shirk.

Lessons drawn from the verse:
1- Slaughtering for anyone other than Allah is major shirk, for it is an act of worship, and dedicating worship to other than Allah is major shirk.
2- Prayer and sacrifice are among the greatest acts of worship.
3- Praying and sacrificing to Allah are prime expressions of gratitude for blessings, as indicated by the causal particle fa (“so”): performing them is the means of thanking Him for the gift of al-Kawthar.