First Samuel 28:6 says that Saul did inquire of the Lord, but 1 Chronicles 10:14 says that he did not:
1Sa 28:6 And when Saul enquired of the LORD, the LORD answered him not, neither by dreams, nor by Urim, nor by prophets.
1Ch 10:13 ¶ So Saul died for his transgression which he committed against the LORD, even against the word of the LORD, which he kept not, and also for asking counsel of one that had a familiar spirit, to enquire of it; 14 And enquired not of the LORD: therefore he slew him, and turned the kingdom unto David the son of Jesse.
How should we understand these seemingly contradictory statements?
John W. Haley argues,
It is sufficient to notice that two different Hebrew words [שָׁאוּל֙ vs. דָרַ֥שׁ ] of diverse meaning are employed here. Or, it may be correctly remarked that Saul’s attempts at inquiry were of so unworthy a nature that it would be an abuse of language to speak of him as really “inquiring of Jehovah.” (Alleged Discrepancies of the Bible, 360)
Matthew Henry comments on 1 Samuel 28:6,
In this distress Saul enquired of the Lord, v. 6. Need drives those to God who in the day of their prosperity slighted his oracles and altars. Lord, in trouble have they visited thee, Isa. 26:16. Did ever any seek the Lord and not find him? Yes, Saul did; the Lord answered him not, took no notice either of his petitions or of his enquiries; gave him no directions what to do, nor any encouragement to hope that he would be with him. Should he be enquired of at all by such a one as Saul? Eze. 14:3. No, he could not expect an answer of peace, for, 1. He enquired in such a manner that it was as if he had not enquired at all. Therefore it is said (1 Chr. 10:14), He enquired not of the Lord; for he did it faintly and coldly, and with a secret design, if God did not answer him, to consult the devil. He did not enquire in faith, but with a double unstable mind. 2. He enquired of the Lord when it was too late, when the days of his probation were over and he was finally rejected. Seek the Lord while he may be found, for there is a time when he will not be found. 3. He had forfeited the benefit of all the methods of enquiry. Could he that hated and persecuted Samuel and David, who were both prophets, expect to be answered by prophets? Could he that had slain the high priest, expect to be answered by Urim? Or could he that had sinned away the Spirit of grace, expect to be answered by dreams? No. Be not deceived, God is not mocked. (Commentary on the Whole Bible, 431; bold is in italics in original)
On 1 Chronicles 10:14, he remarks,
It is said (1 Sa. 28:6) that Saul did enquire of the Lord and he answered him not: but here it is said, Saul did not enquire of God; for he did not till he was brought to the last extremity, and then it was too late. (Ibid., 567; bold is in italics in original)
Robert Jamieson comments on the words and enquired not of the Lord in 1 Chronicles 10:14,
He had done so in form (1 Sam. xxviii. 6), but not in the spirit of a humble penitent, nor with the believing confidence of a sincere worshipper. His enquiry was, in fact, a mere mockery, and his total want of all right religious impressions was manifested by his rushing from God to a wretched impostor in the service of the devil. (JFB, 1:475).
These sources provide satisfactory explanations that resolve the apparent contradiction between 1 Samuel 28:6 and 1 Chronicles 10:14.
These passages should warn us about inquiring of God in a manner, in a way, or at a point in time such that He would regard our doing so as our not inquiring of Him at all.