Charles H. Spurgeon on Psalms 145:18

To call upon God in truth is, first, to repose an implicit confidence in the faithfulness of his promise, and to look for unlimited answers to prayer from the riches of his grace in Christ Jesus. But it is also, in the next place, to feel our own urgent need of the things for which we supplicate, and to realize an earnest and unfeigned concern to obtain them. "What things ye desire when ye pray", said the Lord, "believe that ye receive them, and ye shall have them"; and hence we gather, that the hearty desire, arising out of the consciousness of need, is an integral and inseparable part of genuine and effectual prayer. —Thomas Dale, 1853.

Verses 18-19. God's people are a praying people, a generation of seekers, and such commonly are speeders. God never said to the seed of Jacob, Seek ye my face in vain. They seek his face, righteousness and strength, and he is found of them...The saints alone betake themselves to God and his help, run to him as their sanctuary; others fly from God's presence, run to the rocks, and the tops of the ragged rocks, call to the hills and the mountains; but a child of God goes only and tells his Father, and before him lays open his cause; as good Hezekiah did, when Rabshakeh came out against him; "O Lord, I am oppressed, undertake for me"; or the Church (Isa 33:2), "Be thou our arm every morning, and our salvation in time of trouble." They only sensibly need, and so alone crave and implore divine succour; and God will not suffer his people to lose the precious treasure of their prayers. "The Lord is nigh unto all them that call upon him; he will fulfil their desire, he will hear their cry", etc. That God who prepares his people's heart to pray, prepares also his own ear to hear; and he that promises to hear before we call, will never deny to hearken when we cry unto him. As Calvin saith: "Oppressions and afflictions make man cry, and cries and supplications make God hear." —F. E., in "The Saint's Ebenezer," 1667.