5. EVERYONE MUST OPEN THEIR HEARTS TO CHRIST JESUS

Everyone, whether a child of the covenant or not, at the first, principal conversion experience a moment when, knowingly or unknowingly, a deliberate choice is made to follow Jesus. This may be called a commitment.
The covenant that God makes with the believer is unilateral in its origin, but mutual in its effect. At some stage of our lives the promises of the covenant must be accepted (cp. Acts 3:19,25,26) while the Lord Jesus Christ must be accepted as our Saviour. (John 1:11-13) This does not happen over and above the covenant, but as a consequence of the covenant. Jesus, for example, said about Zacchaeus: "Today salvation has come to this house, because this man, too, is a son of Abraham." (Luke 19:9)
That means that although Zacchaeus was a son of Abraham, and for that reason a child of the covenant, his salvation only came at the moment he invited Jesus into his home and into his heart.