The Lord is nigh unto all them that call upon him: to all that call upon him in truth.

“"The Lord is nigh unto all that call upon Him" (ver. 18). Where then is that, "Then shall they call upon Me, and I will not hear them"? See then what follows: "all who call upon Him in truth." For many call upon Him, but not in truth. They seek something else from Him, but seek not Himself. Why lovest thou God? "Because He hath made me whole." That is clear: it was He that made thee so. For from none else cometh health, save Him. "Because He gave me," saith another, "a rich wife, whereas I before had nothing, and one that obeyeth me." This too He gave: thou sayest true. "He gave me," saith another, "sons many and good, He gave me a household, He gave me all good things." Dost thou love Him for this? ...Therefore if God is good, who hath given thee what thou hast, how much more blessed wilt thou be when He hath given thee Himself! Thou hast desired all these things of Him: I beseech thee desire of Him Himself also. For these things are not truly sweeter than He is, nor in any way are they to be compared to Him. He then who preferreth God Himself to all the things which he has received, whereat he rejoiceth, to the things he has received, he "calleth upon God in truth." ...”

“The Lord is nigh unto all them that call upon him,.... He is not only nigh unto them in relation, being their near kinsman, brother, father, husband, and head, but with respect to place and presence; not in a general way, as he is the omnipresent God, and so nigh to all, and from whose presence there is no fleeing; but in a special way, he is so nigh to them as he is not unto others, Deu 4:7. He is in their hearts, and dwells there by faith, and they dwell in him; his blood is sprinkled in their consciences, and his righteousness is unto them and upon them; his salvation is brought near to them, to their very hearts, and they are nearer that than when they first believed; he is nigh to them that call upon him, for Christ is equally called upon as the Father; see Co1 1:2; so as to give them what they ask of him, and to help them in all their times of need; to all that call upon him in truth; in faith and with fervency, constantly and importunely, and in the sincerity and uprightness of their hearts; with true hearts, cordially and affectionately; their hearts and mouths agreeing together, as Kimchi observes.”