New Defender's Study Bible Notes
3:17 mine own hand. Possibly because of poor eyesight, Paul seems to have dictated many of his letters, confirming that they were indeed his by his personal signature at the end. Only occasionally did he feel it necessary to mention this, however, as it would normally have been obvious to their recipients. In this case, however, he was concerned that the church had been misled by a letter falsely claiming to be from him (II Thessalonians 2:2), so he reminded them here to always look for his personal signature.