we ourselves … groan: The word groan describes a deep and frustrated longing for God to rescue us from the suffering and oppression of this life (see Exodus 3:7; Lamentations 1:22; Ezekiel 24:17; 2 Corinthians 5:2).
who have the firstfruits of the Spirit: In the Old Testament, first harvest or firstfruits refers to offering the first and best part of a crop to God (see Exodus 23:19; Leviticus 2:12; 23:10; compare 1 Corinthians 15:20, 23). In the same way, the Holy Spirit is God’s promise that he will finish the work he has begun in us (see Ephesians 1:14).
Although God has already adopted believers as his children, we do not yet enjoy all the rights of that adoption. Our inheritance is still in the future (see Romans 8:17). In this life, Christians live between what God has already done and what he will fully reveal in the future.