Come unto Me, all ye that labour and are heavy laden, and I will give you rest. Take My yoke upon you, and learn of Me; for I am meek and lowly in heart: and ye shall find rest unto your souls. – Matthew 11:28, 29

It is very evident that the rest which we are to find is a rest which grows entirely out of our spirits being conformed to the spirit of Christ. “Learn of Me, and ye shall find rest.” It is then a spiritual rest altogether independent of circumstances. It is a vain idea of ours, to suppose that if our circumstances were altered, we should be more at rest. My brother, if you cannot rest in poverty, neither would you in riches; if you cannot rest in the midst of persecution, neither would you in the midst of honor. It is the spirit within that gives the rest, that rest has little to do with anything without. Men have sat on thrones and have found them uneasy places, while others on the rack have declared that they were at rest. The spirit is the spring of rest, as for the outward surroundings they are of small account. Let but your mind be like the mind of Christ, and you shall find rest unto your souls: a deep rest, a growing rest, a rest found out more and more, an abiding rest, not only which you have found, but which you shall go on to find. Justification gave you rest from the burden of sin, sanctification will give you rest from molesting cares; and in proportion as it becomes perfect, and you are like your Saviour, your rest shall become more like that of heaven.

In describing the second rest there is more said concerning Him than in the first. In the first part of our text it only says, “I will give you rest;” but in the second part His character is more fully explained-“For I am meek and lowly in heart;” as if to show that as believers grow in grace, and enjoy more rest, they see more of Jesus and know more of Him. All they know when sin is pardoned is that He gives it, perhaps they hardly know how; but afterwards when they come to rest in Him in sweet fellowship, they know more of His personal attributes, and their rest for that very reason becomes more deep and perfect. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0969.cfm