Rom 8:17 Now if we are children, then we are heirs—heirs of God and co-heirs with Christ, if indeed we share in his sufferings in order that we may also share in his glory.
The word “If” is used constantly qualifying those who are truly in the faith. You suffer as Christ for the good of others. It is this sacrificial love that demonstrate your family line. These are the children of his likeness and the heirs.
You are an heir proved by the suffering of the cross. The cross is not the sin you gave up or the normal trials of everyday life but those suffered for Christ’s sake to complete his mission in love. These acts of valor prove your allegiance.
You are heir in the likeness of Christ. It isn’t the size of the battle but it is your engagement in the war. This proves who you are and what family you belong.