It breaks God’s heart when we don’t trust Him. That is the theme of Isaiah 50.
God had put Israel away (divorced) them for a time, but it was because of their sin (v.1). When He called them back, they would not answer or believe Him – despite His ability to do mighty things like dry up a sea (v.2-3).
The example of the Servant (the Messiah) is given. He does God’s will, speaking truth, surrendering to the Lord, even suffering as the Father wanted Him to (v.4-6). The whole time, He just trusted the Lord, believed the Lord, knowing that He would not be ashamed (v.7-9).
In the same way, those who fear the Lord should trust the Lord and ‘stay’ (depend) upon the Lord (v.10). Those who trust in their own ‘light’ will not have any help from God. Instead they will ‘lie down in sorrow’.
Life without God is a dark place. It is a lonely place, a sorrowful place. We need God. We should trust God. We should depend on Him for everything, all the time. He can and will deliver us, just like He worked powerfully for and through our Saviour, the Lord Jesus Christ.