For ye know what commandments we gave you by the Lord Jesus.
By the Lord Jesus - by His authority, not by our own. He uses the strong term "commandments" х parangelias (G3852)], in writing to this church, not long founded, knowing that they would take in a right spirit this intimation that he spake with divine authority. He seldom uses the term in writing subsequently, when his authority was established to others. 1 Corinthians 7:10; 1 Corinthians 12:17; and 1 Timothy 1:5 (1 Thessalonians 4:18, where the subject accounts for the strong expression) are the exceptions. "The Lord" marks His paramount authority, requiring implicit obedience.