In the sense that our Heavenly Father has taken up residence in His New Temple ( John 14:23 ( I Corinthians 6:19 ), the Church has reached the 'fullness of Christ'', but the Church, as the Kingdom, is ever-expanding, and thus, in that sense, has need still of 'The Gifts of the Spirit ( I Corinthians 14 )
On a Corporate level, then, the Church has reached full maturity, and attained this 'stature', but on a personal &; individual level, there are those within the Body ( as well as those outside ) who have not yet reached that level of maturity, so it is for these that the Gifts must be employed!
Another reason for the Continuation of the Gifts is elaborated well in the apostle's words to the Church at Corinth ( I Corinthians 12:11 ), 'But one and the same Spirit works all these things, distributing to each one individually as He wills'. It could be argued that since the Holy Spirit was an eschatological phenomenon , that He is no longer relevant to our present situation! However, this is where many traditional Trinitarians get it wrong; by making too much of a distinction between, as they say, 'the three persons of the God-head', it causes some believers to go too far the other way, and claim that since the Fulfillment of the Eschaton, and now that our Heavenly Father has become 'all in all' ( I Corinthians 15:28 ), that there is no more Holy Spirit, or at least that the Gifts & Baptism of the Holy Spirit have ceased.
As our Heavenly Father is Eternal, so in that sense are His Gifts Eternal! He still gives the Gifts as needed and where warranted! The Fact of the Matter is that men are still men; just as in the apostle Paul's day, where 'God has dealt to each one a measure of faith' , so in our day, there are varying levels of faith. Some believe that they 'may eat all things' ( Romans 14:2 ), while others esteem '[ one] day above another' ( Romans 14:5 ). As the case may be, not every individual has reached the same level of maturity within the Body! It is those who must be taught, not the knowledge of God, though there are arguably those as well, but the fullness of our Freedom in Christ, and what it truly means that we are 'free indeed' ( John 8:36 )!
Since we ( corporately ) have received this 'fullness', let us employ His Gifts as well, when & where needed, trusting to our Heavenly Fathers Provision, Wisdom & Guidance, as we act the part of 'healing leaves' in our area of the world. Let us Continue to edify the Body with the Gifts which our Heavenly Father has bestowed upon us, and which Shine out through us! If our Gift is to teach, let us teach those who need teaching, if love, those who need loving, if different tongues, those who need to hear in different tongues, if healing, those who need healing; remembering always that it is the Spirit within who shines out through our action!
Glorying & Gloriously,
Charles Haddon Shank