“in faithfulness.” Here in Jeremiah 32:41, God reminds us that He is a faithful God. The reason we can trust His promises is that He is faithful and He does not lie, and He made promises to Israel that they would have the Promised Land. Here in Jeremiah, He promises to plant Israel in the land, thus being faithful to what He had said.
“whole soul.” Here in Jeremiah 32:41, the word “soul” means “self” in the sense of God’s thoughts, emotions, and attitudes. God does not have a “soul” that gives him life, like humans do.
[For more on “soul,” see Appendix 7, “Usages of ‘Soul.’”]