The words of God.
John uniquely continued with this poetic theological presentation of John the Baptist to his disciples. God (ὁ Θεὸς) sent the one (ὃν γὰρ ἀπέστειλεν) who speaks (λαλεῖ) the words of God (τὰ ῥήματα τοῦ Θεοῦ). Thus, he gives (δίδωσιν) the Spirit (τὸ Πνεῦμα) without measure or limit (οὐ γὰρ ἐκ μέτρου). Jesus, the one sent from God, possess the fullness of the spirit, the Holy Spirit. Thus, he can distribute or give this Spirit without any limitations. God the Father, through Jesus, gives the Holy Spirit freely. This is a very strong trinitarian theological statement uttered by John the Baptist, via this gospel. Do you believe in the Trinity?