# obtained these things

These include knowing Christ, knowing the power of his resurrection, sharing in Christ's suffering, and being united with Christ in his death and resurrection. Paul urges the believers at Philippi to follow his present example because of heaven and the new bodies that wait for believers. He speaks, knowing that God will allow him to live forever in heaven, as if he were a runner racing for the finish line. 

# or am already perfect

"so I am not yet perfect" or "so I am not yet mature"

# but I press on

"but I keep trying"

# to take hold of that for which I was taken hold of by Christ Jesus

"to receive these things for which Jesus claimed me as his own". Receiving spiritual things from Christ is spoken of as if Paul could grasp them with his hands, and Jesus choosing Paul to belong to him is spoken of as if Jesus grasped Paul with his hands.