For here have we no continuing city, but we seek one to come. – Hebrews 13:14

When Israel received water out of the rock it was not bitter, but this water came out of the sand. To this day in the desert water is found in different places, but where it oozes up from a sandy bed it is almost without exception so brackish and bitter, by reason of the sand, that it is not fit for human drinking; and even the camels, unless they are sore pressed, turn away from it with great aversion. The sand has tainted it, the flavour of earth has got into the blessing. So it is with most of our blessings; by reason of our sin and infirmity too much of the flavour of earth enters into the gift of heaven. Our common mercies, when we receive them direct from heaven as God gives them, are mercies indeed-cool, flowing streams that gush from the rock of His favor; but we are so apt to trace them to the creature, so ready to look upon them as derived from earth instead of coming from heaven; and just in that proportion may we expect to find bitterness in them. What can you hope for in a wilderness, but productions congruous to it? Canaan! who looks for bitterness there? Is it not the land that flows with milk and honey? Sweet land, when shall we reach thee? Thy sweetness is but congruous to thyself: But here, in this wilderness, where we have no continuing city, who looks for the streams of Lebanon? who hopes to find Canaan’s fruits in the wilderness of Sin? As well seek to gather from the briny sea the sweet fruits of the palm or the luscious clusters of the vine, as hope to find, amidst these changing scenes, comforts that shall be all comfortable and joys that shall be all joyous. No, they will be comforts, but they will be often embittered; they will be joyous somewhat, but the earthy flavour in them will make us remember that this is not our rest.~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0987.cfm

For whom the Lord loveth He chasteneth, and scourgeth every son whom He receiveth… Now no chastening for the present seemeth to be joyous, but grievous: nevertheless afterward it yieldeth the peaceable fruit of righteousness unto them which are exercised thereby.- Hebrews 12:6,11

God may touch us, and probably has done so or will, in points most vital. To be tried in the loss of some of your superfluities, my brethren, is but little; but to lose even the little that you had to live upon, to be brought to straitness of bread, this is real tribulation. To have the hand put forth to touch your bone and your flesh, this is affliction. Believe me, our virtues and graces look very fine, and we think much of them until they undergo that ordeal, but that test often takes from them their gloss and beauty; we find how great our weakness is when the very marrow of our bones seems to be a den in which pains, like robbers, hide themselves. God may touch you in the most beloved object of your heart. It is not one child that is taken out of many, but the only one; it is not a friend, or distant relative, but the partner of your bosom is laid low. Do not wonder if the trial affects you greatly, and comes home to your soul and heart. It is one of God’s determinations that trials shall not be mock trials with his servants, and the grace given shall not be imaginary, but true. God never plays at chastening His children. No trial for the present seemeth to be joyous, but grievous. By the blueness of the wound the heart is made better; if it does not bruise, it doth not benefit. Very much in proportion to the bitterness felt will be the benefit that will come of it.  ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0987.cfm

…and they went three days in the wilderness, and found no water. And when they came to Marah, they could not drink of the waters of Marah, for they were bitter_ Exodus 15:22,23

Do not be in a hurry to change your trials, dear friends…We have known those who were in good health, but discontented because they had no wealth; they have gained wealth at last, but with an injured constitution they have had no power to enjoy it. If we could choose our trials, we might well remember the wisdom of the old philosopher, who told the people oppressed by a tyrant to be content with his tyranny, “for,” said he, “it is with oppressors as with mosquitoes, let those suck which are now upon you, for if you drive those off, the fresh ones which will succeed them will be hungrier than those that are there now: better be content with the tyranny you have, than seek a new one.” It is much the same with the trials we now face – you will get used to them by degrees: they will spend their force. Desire for a change of trials may only be a wish for a worse affliction, for whether was the worse, to have no water, or to have the water and to find it so bitter that you could not drink it?

Yet when God changes the trial be well satisfied that it should be changed. You may anticipate, Christian, that you will have your trial changed: indeed, you must reckon that it is so. I mean that if today it is smooth sailing with you, though yesterday waves rolled mountains high, it is only a change of trial; you are now tried by prosperity, which may prove to be a more severe test for you than adversity. Is the wind balmy, blowing in from the south? Is it but another trial for thee, be sure of that, for they who have withstood the northern blast and grown the ruddier and stronger for its influence, have often grown faint and weary under softer airs. Watch thou in all things, thy trials are with thee constantly; the crucible is changed, the fire still burns. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0987.cfm

And when they came to Marah, they could not drink of the waters of Marah for they were bitter: therefore the name of it was called Marah. And the people murmured against Moses, saying, What shall we drink? And he cried unto the Lord, and the Lord showed him a tree, which when he had cast into the waters, the waters were made sweet. -Exodus 15:23-25.

What a sudden change from the sound of the timbrel (vv.21-22) to the voice of murmuring! You saw the maidens dancing three days ago, and you little dreamed that they would make part of yonder clamorous throng who surround the servant of God, and cry, “What shall we drink?” Such are the changes of our outward conditions and of our inward feelings, so fickle and so mutable is man. What is there that can be rested upon in this mortal life? We say to-day, “My mountain standeth firm, I shall never be moved;” to-morrow, terra firma there is none, and we are tossed upon a stormy sea. Our life is like an April day, the sunshine alternates with the shower; or like each day of all the year, the morning and the evening are needful to complete it. Quick on the heels of light treads the darkness, followed with equal haste by light again. The sun’s rule, at this golden hour, is but temporary; he must abdicate in favor of the usurping stars, but they, in their turn, must give way before his lordly presence yet again. This world, which is our inn, owns to the sign of the “chequers”-the blacks and whites are everywhere. We can be sure of nothing between here and heaven of the things which are seen; but of this we may be certain, that underneath all the outward change there is the immutable love of God towards His people, and that, after all, the change lies only in the seeming things, not in the things which truly are; for the things which are not seen are eternal and changes come not there; it is but in the things which are seen that the change occurs. Let us set the less store by earth, because its fashion abides not. Let us prize heaven more, because it cannot fade. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0987.cfm