Jesus invites those who know their need, those who are poor in spirit (cf. Mt 5:3), to take the initiative and come to him and drink (v. 37). Drinking refers to believing (cf. v. 38), which means aligning oneself with him, trusting him, receiving his teaching and obeying his commands. Such faith will enable one to receive the Spirit and enter an abiding relationship with Christ after his glorification. All of this is based on who God is and what he has done for us. When we believe we open our hands to receive what his grace offers--we come and drink. Jesus who brings God's gracious offer of life.