Paul says the foundation is Christ.
1 Corinthians 3:11 For no one can lay a foundation other than that which is laid, which is Jesus Christ.
Romans 9:30-32 30What shall we say, then? That Gentiles who did not pursue righteousness have attained it, that is, a righteousness that is by faith; 31but that Israel who pursued a law that would lead to righteousness did not succeed in reaching that law. 32Why? Because they did not pursue it by faith, but as if it were based on works. They have stumbled over the stumbling stone, 33as it is written,
"Behold, I am laying in Zion a stone of stumbling, and a rock of offense; and whoever believes in him will not be put to shame."
1 Corinthians 10:1-8 1For I want you to know, brothers, that our fathers were all under the cloud, and all passed through the sea, 2and all were baptized into Moses in the cloud and in the sea, 3and all ate the same spiritual food, 4and all drank the same spiritual drink. For they drank from the spiritual Rock that followed them, and the Rock was Christ. 5Nevertheless, with most of them God was not pleased, for they were overthrown in the wilderness.
6Now these things took place as examples for us, that we might not desire evil as they did. 7 Do not be idolaters as some of them were; as it is written, "The people sat down to eat and drink and rose up to play." 8 We must not indulge in sexual immorality as some of them did, and twenty-three thousand fell in a single day.
9We must not put Christ to the test, as some of them did and were destroyed by serpents, 10nor grumble, as some of them did and were destroyed by the Destroyer. 11Now these things happened to them as an example, but they were written down for our instruction, on whom the end of the ages has come. 12Therefore let anyone who thinks that he stands take heed lest he fall.
So does Peter....
1 Peter 2:4-8 4As you come to him, a living stone rejected by men but in the sight of God chosen and precious, 5 you yourselves like living stones are being built up as a spiritual house, to be a holy priesthood, to offer spiritual sacrifices acceptable to God through Jesus Christ. 6For it stands in Scripture: "Behold, I am laying in Zion a stone, a cornerstone chosen and precious, and whoever believes in him will not be put to shame."
7So the honor is for you who believe, but for those who do not believe, "The stone that the builders rejected has become the cornerstone,"
8and "A stone of stumbling, and a rock of offense."
They stumble because they disobey the word, as they were destined to do.
There isn’t any contradiction between Christ and his Church.