CIC 2570 When God calls him, Abraham goes forth “as the Lord had told him”;1 Abraham’s heart is entirely submissive to the Word and so he obeys. Such attentiveness of the heart, whose decisions are made according to God’s will, is essential to prayer, while the words used count only in relation to it. Abraham’s prayer is expressed first by deeds: a man of silence, he constructs an altar to the Lord at each stage of his journey. Only later does Abraham’s first prayer in words appear: a veiled complaint reminding God of his promises which seem unfulfilled.2 Thus one aspect of the drama of prayer appears from the beginning: the test of faith in the fidelity of God.

1 Gen 12:4.
2 Cf. Gen 15:2 f.