The Apostle [Paul] is concerned about the ‘development’ of that which is already in existence, rather than about arriving at something which is hitherto non-existent … Perhaps the clearest statement of the point is … in Philippians 3:10, where he says that his greatest desire is ‘that I may know him’. Does he mean by that, that he did not know Him at all, and that he is longing to have a knowledge of Christ? Of course not. What he is saying is this: ‘I do know Him, but I want to know Him much more, I want to have a deeper knowledge.’ He longs for an ‘increase’ and for the perfecting of the knowledge he already has.
To put the matter finally beyond dispute we may turn to the paradoxical statement of Philippians 3:12-15. Paul begins, ‘Not as though I had already attained, either were already perfect'; and then continues, ‘Let us therefore, as many as be perfect, be thus minded’ (v15) … There is no real contradiction, of course. What he means is that all true Christians already have the knowledge essential to salvation and are perfect in that sense … So he says, ‘Let us therefore, as many as be perfect, be thus minded’. Then he goes on to say, ‘If in any thing ye be otherwise minded, God shall reveal even this unto you’. There are still aspects of the faith and of the truth which we do not yet know; they will be revealed to us. As regards the faith we have, and our present position on the foundation, Christ Jesus, there is a sense, therefore, in which we are already perfect. But we must also go on to perfection. We have not arrived, have not ‘already attained’ (v12). We are now growing in this knowledge that we have. We are now coming into it. It is because we are in it already that we can grow and develop in and through it.