1 Samuel 15 (KJV)

22 And Samuel said, Hath the Lord as great delight in burnt offerings and sacrifices, as in obeying the voice of the Lord? Behold, to obey is better than sacrifice, and to hearken than the fat of rams.
23 For rebellion is as the sin of witchcraft, and stubbornness is as iniquity (wickedness) and idolatry. Because thou hast rejected the word of the Lord, he hath also rejected thee from being king.

Obeying God's word will always take precedence over any sacrifice.  This includes tithes. ~ Karmen

24 And Saul said unto Samuel, I have sinned: for I have transgressed the commandment of the Lord, and thy words: because I feared the people, and obeyed their voice.
25 Now therefore, I pray thee, pardon my sin, and turn again with me, that I may worship the Lord.

26 And Samuel said unto Saul, I will not return with thee: for thou hast rejected the word of the Lord, and the Lord hath rejected thee from being king over Israel.
27 And as Samuel turned about to go away, he laid hold upon the skirt of his mantle, and it rent.
28 And Samuel said unto him, The Lord hath rent the kingdom of Israel from thee this day, and hath given it to a neighbour of thine, that is better than thou.

35 And Samuel came no more to see Saul until the day of his death: nevertheless Samuel mourned for Saul: and the Lord repented (apologized to himself) that he had made Saul king over Israel.