Please see the below repost of mine fir your consideration from another forum regarding this topic which also addresses the question of what is "that which is perfect ".
The subject of spiritual gifts is difficult to understand, hence very controversial, and equally difficult to unravel.
First, look at the way Paul began the Corinthian letter starting at 1 Cor1:10 wherein he's discussing contentions and divisions in Corinth and the need for unity which sets the stage for the rest of 1 Cor; and keep in mind, this was written to them in their time, addressing their near term issues, and not to us nor considering some future event. And note that the church was a fledgling body with little to guide and hold it together, prone to division, contention, and falling away, such as was also warned of in Heb 6 as well.
You have to first ask yourself what is "that which is perfect"? It's not referring to Jesus or his return, Jesus is not a "that".
The answer can be found in Eph 4:13 wherein it states 'till we all come to the unity of the faith unto a perfect man, that being the perfection of the body of Christ: this then addressing the previous need for the miraculous manifestation of the gifts, parts of the body as equated to the body of a man, noted in 1 Cor 12:8-10. We now have the bible to guide us and no longer need such miraculous piece meal parts of the body. Also note, the interlinear says "should come" not "is come" which also supports the idea of the possible replacing of something permanent for the temporal nature of the gifts.
The "face to face" and "known as we are known" relates to the distinction between the OT writings when reading Moses, and coming to Christ via the NT and the comparison to the veil when reading Moses, and we now, and they then, being able to look into a glass (mirror) and seeing a reflection of Christ as opposed to our own image.
To piece it all together, you must consider the gifts and their need at that time, all being necessary in the early church to edify and grow it, such as by tongues, being a sign to unbelievers, miracles, prophesy, etc.
I've posted all the pertinent parts of scriptures from 1 Cor 12, 13, Gal 3, and Eph 4. Look closely at the similarity of words and phraseology used and piece those similar words and phrases together to get an understanding of their meaning as relates to the subject.
1 Cor 12:8-27
8For to one is given by the Spirit the word of wisdom; to another the word of knowledge by the same Spirit; 9To another faith by the same Spirit; to another the gifts of healing by the same Spirit; 10To another the working of miracles; to another prophecy; to another discerning of spirits; to another divers kinds of tongues; to another the interpretation of tongues: 11But all these worketh that one and the selfsame Spirit, dividing to every man severally as he will.12For as the body is one, and hath many members, and all the members of that one body, being many, are one body: so also is Christ.
14For the body is not one member, but many.
19And if they were all one member, where were the body? 20But now are they many members, yet but one body.
27Now ye are the body of Christ, and members in particular.
1 Cor 13:8-12
8Charity never faileth: but whether there be prophecies, they shall fail; whether there be tongues, they shall cease; whether there be knowledge, it shall vanish away. 9For we know in part, and we prophesy in part. 10But when that which is perfect is come, then that which is in part shall be done away. 11When I was a child, I spake as a child, I understood as a child, I thought as a child: but when I became a man, I put away childish things. 12For now we see through a glass, darkly; but then face to face: now I know in part; but then shall I know even as also I am known.
2 Cor 3:7-18
7But if the ministration of death, written and engraven in stones, was glorious, so that the children of Israel could not stedfastly behold the face of Moses for the glory of his countenance; which glory was to be done away: 8How shall not the ministration of the spirit be rather glorious? 9For if the ministration of condemnation be glory, much more doth the ministration of righteousness exceed in glory. 10For even that which was made glorious had no glory in this respect, by reason of the glory that excelleth. 11For if that which is done away was glorious, much more that which remaineth is glorious.
13And not as Moses, which put a vail over his face, that the children of Israel could not stedfastly look to the end of that which is abolished: 14But their minds were blinded: for until this day remaineth the same vail untaken away in the reading of the old testament; which vail is done away in Christ. 15But even unto this day, when Moses is read, the vail is upon their heart. 16Nevertheless when it shall turn to the Lord, the vail shall be taken away. 17Now the Lord is that Spirit: and where the Spirit of the Lord is, there is liberty. 18But we all, with open face beholding as in a glass the glory of the Lord, are changed into the same image from glory to glory, even as by the Spirit of the Lord.
Gal 3:23-25
23But before faith came, we were kept under the law, shut up unto the faith which should afterwards be revealed. 24Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith. 25But after that faith is come, we are no longer under a schoolmaster.
Eph 4:11-16
11And he gave some, apostles; and some, prophets; and some, evangelists; and some, pastors and teachers; 12For the perfecting of the saints, for the work of the ministry, for the edifying of the body of Christ: 13Till we all come in the unity of the faith, and of the knowledge of the Son of God, unto a perfect man, unto the measure of the stature of the fulness of Christ: 14That we henceforth be no more children, tossed to and fro, and carried about with every wind of doctrine, by the sleight of men, and cunning craftiness, whereby they lie in wait to deceive; 15But speaking the truth in love, may grow up into him in all things, which is the head, even Christ: 16From whom the whole body fitly joined together and compacted by that which every joint supplieth, according to the effectual working in the measure of every part, maketh increase of the body unto the edifying of itself in love.