1 Corinthians 3:21

All things are yours] To him who is united to Christ all things belong, contributing to the growth of his Christian character and the increasing perfection of his spiritual life. He learns from all teachers; the world provides him with the means of growth in grace, for all his experiences in its possessions and work influence his spiritual life; life is full of divine meaning and purpose; death is revealed to him as the gate of life; he is delivered from any danger to his spirit arising from the perplexities of the present or the problems of the future (things to come).

23. Ye are Christ's] i.e. you belong to Christ, not to Paul or Apollos or Cephas. And Christ is God's] i.e. God is over all; even Christ belongs to Him. And as we are Christ's, we belong to God. Theodoret remarks, 'Christ belongs to God, not as God's creature, but as God's Son.' Perhaps the Apostle simply desires to assert that God is supreme over all: cp. 1 Corinthians 15:24; John 4:34.

Glory in men] boast of their preference for this or that teacher, as they had been doing (1 Corinthians 1:12).