Contradiction with Psalms 89:21
This verse states that God's hand shall be established with him, and his arm shall strengthen him, which contradicts Psalms 89:43 where it is suggested that the sword's edge is turned back and does not give victory.
Psalms 89:21: With whom my hand shall be established: mine arm also shall strengthen him.
Contradiction with Psalms 20:6
Here it is said that the Lord saves his anointed and will answer him from his holy heaven with saving strength, contradicting the notion in Psalms 89:43 of a lack of victory.
Psalms 20:6: Now know I that the LORD saveth his anointed; he will hear him from his holy heaven with the saving strength of his right hand. [his holy...: Heb. the heaven of his holiness] [with...: Heb. by the strength of the salvation of]
Contradiction with Psalms 18:39
This verse affirms that God has girded the psalmist with strength for battle and subdued enemies, contrasting with the defeat implied in Psalms 89:43.
Psalms 18:39: For thou hast girded me with strength unto the battle: thou hast subdued under me those that rose up against me. [subdued: Heb. caused to bow]
Contradiction with Isaiah 54:17
It declares that no weapon formed against shall prosper, and every tongue that rises in judgment shall be condemned, which contradicts the idea of being turned back in battle as suggested in Psalms 89:43.
Isaiah 54:17: No weapon that is formed against thee shall prosper; and every tongue [that] shall rise against thee in judgment thou shalt condemn. This [is] the heritage of the servants of the LORD, and their righteousness [is] of me, saith the LORD.