“Do not be deceived” is a repeated warning throughout Scripture reminding believers to stay alert, grounded in truth, and discerning. Satan, false teachers, worldly desires, and even our own hearts can lead us away from God if we are careless. Christ calls His people to test everything by the Word of God, walk in wisdom, and refuse the lies that lead to sin, compromise, and destruction. God is not mocked — whatever a person sows, that they will also reap.