Quote from A Course in Miracles Text Chapter 19 - THE ATTAINMENT OF PEACE.

T-19.I.12. Faith is as easily exchanged for knowledge as is the real world. 2 For faith arises from the Holy Spirit's perception, and is the sign you share it with Him. 3 Faith is a gift you offer to the Son of God through Him, and wholly acceptable to his Father as to Him. 4 And therefore offered you. 5 Your holy relationship, with its new purpose, offers you faith to give unto your brother. 6 Your faithlessness has driven you and him apart, and so you do not recognize salvation in him. 7 Yet faith unites you in the holiness you see, not through the body's eyes, but in the sight of Him Who joined you, and in Whom you are united.