'Now there are diversities of gifts (charismata), but the same Spirit. And there are diversities of ministrations, and the same Lord. And there are diversities of workings, but the same God, who works all things in all.'
Paul then goes on the point out that there are in fact diversities of spiritual gifts (charismata - 'gifts of grace'), all given and inspired by the same Spirit, differing ministries in the church, all performed and empowered under the same Lord, many types of workings in creation (or in all the churches, or in all Christians), but all energised through the One God, Who works everything ('all things') everywhere (or 'in everyone'). Thus there is one Spirit, one Lord and one God Who is/are responsible for true spiritual gifts, for true spiritual ministry and for all that goes on either in Christians or everywhere. Note that the stress is on oneness, thus stressing also the oneness in triunity of the Spirit, the Lord and God Whose activity unites the people of God as one.
(We use the verb ‘is/are' advisedly. Our problem when speaking of the triune God is that we have no human language with which to adequately describe Him. In the Old Testament the word for ‘God' was plural with a singular verb emphasising this dilemma. There is nothing on earth that remotely parallels God. God is One and yet revealed in plurality. ‘Is' emphasises the unity, ‘are' emphasises the plurality. Neither is adequate to express the full truth about God).
Not all have the same gifts. And yet, as he is at pains to stress, if they are genuine they come from the one Spirit. Diverse gifts do not indicate disunity and disharmony, for each is necessary in the fulfilling of the church's service and ministry This stress on unity is continued by emphasising that service within the church is through the one Lord, and that the bringing about of ‘all things' in all (giving overall coverage of anything that takes place through the church, or indeed in creation) are the working of the one God. So, as with the Lord's Supper earlier, there is a stress both on the Godward side, and here the oneness of God is revealed in triunity, and on the oneness of all believers because all are in union with Christ's body, and all that they have comes from the one God. Note on the Godward side, the emphasis on the triunity of God; one Spirit, one Lord, one God (compare 1 Corinthians 8:6).
All ministries in the church are administered and empowered by the same Lord. This is not to separate the functions but to combine the activities of the Godhead in provision for His people. Ministries and gifts are seen as part of one whole in 1 Corinthians 12:28-30, the provision of both Spirit and Lord.
And it is God Who works everything everywhere/in everyone. This could mean everything in all the churches worldwide, or everything in creation. In context possibly it is the former that is intended. All that is true that occurs in the churches is of God's working. But we would not exclude the other.