I’m afraid it wasn’t just one commandment, Appy. Notice the context in vv8-10:
“v8 And you shall again obey the LORD, and observe all His commandments which I command you today. 9 Then the LORD your God will prosper you abundantly in all the work of your hand, in the offspring of your body and in the offspring of your cattle and in the produce of your ground, for the LORD will again rejoice over you for good, just as He rejoiced over your fathers; 10 if you obey the LORD your God to keep His commandments and His statutes which are written in this book of the law, if you turn to the LORD your God with all your heart and soul.
Then again, he says in v11: “For this commandment which I command you today is not too difficult for you, nor is it out of reach.”
Please keep reading the next few verses as he makes it clear he’s not speaking of just one commandment, but all the Law of Moses.
Acts 11
4 Starting from the beginning, Peter told them the whole story: 5 “I was in the city of Joppa praying, and in a trance I saw a vision. I saw something like a large sheet being let down from heaven by its four corners, and it came down to where I was. 6 I looked into it and saw four-footed animals of the earth, wild beasts, reptiles and birds. 7 Then I heard a voice telling me, ‘Get up, Peter. Kill and eat.’
8 “I replied, ‘Surely not, Lord! Nothing impure or unclean has ever entered my mouth.’
9 “The voice spoke from heaven a second time, ‘Do not call anything impure that God has made clean.’ 10 This happened three times, and then it was all pulled up to heaven again.