And when He returned, He found them asleep again, for their eyes were heavy; and they did not know what to answer Him. – Mark 14:40

Beloved brother, say unto thy soul, thus-“here have I come to the throne of grace to worship God and seek His blessing, and I am not going away till I have done this; I will not rise from my knees, because I have spent my customary minutes, but here will I pray till I find the blessing.” Satan will often leave off tempting when he finds you thus resolute in prayer. Brethren, we need waking up. Routine grows upon us. We get into the mill-horse way-round, and round, and round the mill. From this may God save us. It is deadly. A man may pray twenty years with regularity, as far as the time goes, and the form goes, and never have prayed a single grain of prayer in the whole period. One real groan fetched from the heart is worth a million litanies, one living breath from a gracious soul is worth ten thousand collects. May we be kept awake by God’s grace, praying without ceasing.

We must take care, dear brethren, if we would perform this duty, that we fight against anything like despair of being heard. If we have not been heard after six times we must, as Elijah, go again seven times; if our Peter is in prison, and the church has prayed God to liberate him, and he still is in fetters bound in the inner prison, let us pray on, for one of these days Peter will knock at the gate. Be importunate, heaven’s gate does not open to every runaway knock. Knock, and knock, and knock again; and add to thy knocking and to thy asking seeking, and be not satisfied till thou gettest a real answer. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/1039.cfm