In Paul’s time, slaves were branded with distinctive marks to show that they belonged to their masters, much as cattle are branded in modern times (Psa 40:6). Paul declared that his body bore marks from the persecution he had endured in Christ’s service. These showed the he belonged to the Lord Jesus.
The apostle name some of these marks of persecution in 2 Corinthians 11:24-25; “Five times received I forty stripes save one. Thrice was I beaten with rods, once was I stoned.”
GALATIANS 6:17 – I [Paul] bear in [on, NIV] my body the marks of the Lord Jesus.