Irenaeus on Keeping the Sabbath
"Irenaeus, bishop of Lyons in the last half of the second century, also gives us lengthy comments on the Sabbath, and his views probably reflect those of Asia Minor, since that is where he was from. He had also been in Rome and may have been influenced by Justin Martyr. Irenaeus, commenting on the grainfield incident (Matt. 12), notes that Jesus did not break the Sabbath, but Irenaeus gives a rationale that applies to Christians, too ..."