Having grown up with Eli as a mentor, Samuel begins to speak for the Lord to all of Israel but doesn’t speak against Eli or his children. Samuel is well respected and listened to during his ministry, but as Samuel reaches old age, he appoints his two sons to stand as judges over Israel. They accepted bribes and corrupted their power as Eli’s sons had before them, forcing the people to cry out that they needed a king to rule and lead them. Samuel is told by God to inform them that a king over them will take a tenth of their grain and their vintage and a tenth of their flocks, among many other things (1 Sam 11-17). This carries the same tenths that were required of the Israelites, of their animals and of their fields, because God was to be their king, and they are rejecting Him as well (1 Sam 8:7-8). Samuel then finds and anoints Saul to be their king, explaining all of his rights and duties and placing him over Israel. Samuel then warns the Israelites that if they and their king serve and obey the Lord then they will be taken care of, but if they rebel or do not obey his commands, God will be against them. It is their disobedience and their rebelling against God that loses His favor and works against them during the Kingdom of Israel.
We know that in the time of the Kings of Israel there were annual tithes collected with some kind of consistency, because in 1 Sam 20:6, David is able to use the annual sacrifice of his people when speaking to Jonathan. David uses this custom of the Israelites as an excuse for his absence in the presence of King Saul, because it would be known at the time that they Israelites had to travel to the temple for this tithe to be submitted and the celebration to follow. Additionally, we know that during the reign of King David, he vows to repair the Temple of the Lord using the riches of the kingdom. This is collected in large part from offerings and from offerings of David’s own personal treasures (1 Chron 29). Throughout both Saul and David’s reign, we see burnt and peace offerings given to the Lord according to required law, especially following great battles with the riches gained therein. When Saul wins the battle against the Amalekites and their king, Agag, he destroys them and takes their best sheep and cattle to sacrifice this to God. But, Samuel tells him that the Lord would much rather have his obedience than the fat of their sacrifices. He calls rebellion the sin of divination and arrogance like idolatry, saying that the Lord hates these sins much more than he likes a sacrifice made to Him (1 Sam 15:22-26).
Even during the time of kings, God makes it very clear, both to Saul through Samuel at the start and to the later kings through his protection over Israel and His people, that obedience and faithfulness to him determines whether he will care for them and defend them from their enemies. The tithes and offerings come and go with acknowledgement of His laws and inclusion in their lives throughout battles and harvests when they turn to the Lord for blessings. It is the fulfillment of their covenant of obedience to him, however, that continually shows direct improvements in the lives of the Israelites.