Take in Psalm 103 - read it through, and marinate in it. For my own words will do no justice to its beauties. I will only make a few observations.
First, note that the psalmist is talking to himself in v. 1-5. In fact, most of the psalm - until v. 20 - is him talking to himself. This is incredibly important. We so often acquire warped views of God. As I think Tozer once said, the most important thing about anyone is what he thinks about God. But in the struggles of life, sometimes we need to take ourselves in hand, grab our souls by the lapels, and say, “Soul, listen to me. Here is your God. Bless the LORD, for all that He does and is.”
The key note comes in v. 7: His salvation of His people now recasts all His other doings with them. Because He rescued His people - all by grace, not because they earned it - everything He does now with them is cast in a mold of grace. Even the hard stuff. When He chides, it’s not forever (9). When we sin, He is merciful (10). When suffering comes, He knows our frame, and restrains it (14).
He is like a father (13). What a blessing, that a Christian - a non-Jew - might read this, and bank on it himself. How? Because there came along Jesus, who called this father “Father.” And we who have trusted in him are united to him, in all that he is. Thus by faith we too might call this God “Father,” and make this psalm our own.